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Loghry HJ, Kwon H, Smith RC, Sondjaja NA, Minkler SJ, Young S, Wheeler NJ, Zamanian M, Bartholomay LC, Kimber MJ. Extracellular vesicles secreted by Brugia malayi microfilariae modulate the melanization pathway in the mosquito host. Sci Rep 2023; 13:8778. [PMID: 37258694 PMCID: PMC10232515 DOI: 10.1038/s41598-023-35940-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 05/26/2023] [Indexed: 06/02/2023] Open
Abstract
Vector-borne, filarial nematode diseases cause significant disease burdens in humans and domestic animals worldwide. Although there is strong direct evidence of parasite-driven immunomodulation of mammalian host responses, there is less evidence of parasite immunomodulation of the vector host. We have previously reported that all life stages of Brugia malayi, a filarial nematode and causative agent of Lymphatic filariasis, secrete extracellular vesicles (EVs). Here we investigate the immunomodulatory effects of microfilariae-derived EVs on the vector host Aedes aegypti. RNA-seq analysis of an Ae. aegypti cell line treated with B. malayi microfilariae EVs showed differential expression of both mRNAs and miRNAs. AAEL002590, an Ae. aegypti gene encoding a serine protease, was shown to be downregulated when cells were treated with biologically relevant EV concentrations in vitro. Injection of adult female mosquitoes with biologically relevant concentrations of EVs validated these results in vivo, recapitulating the downregulation of AAEL002590 transcript. This gene was predicted to be involved in the mosquito phenoloxidase (PO) cascade leading to the canonical melanization response and correspondingly, both suppression of this gene using RNAi and parasite EV treatment reduced PO activity in vivo. Our data indicate that parasite-derived EVs interfere with critical immune responses in the vector host, including melanization.
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Affiliation(s)
- Hannah J Loghry
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
| | - Hyeogsun Kwon
- Department of Entomology, College of Agriculture and Life Sciences, Iowa State University, Ames, IA, USA
| | - Ryan C Smith
- Department of Entomology, College of Agriculture and Life Sciences, Iowa State University, Ames, IA, USA
| | - Noelle A Sondjaja
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Sarah J Minkler
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Sophie Young
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Nicolas J Wheeler
- Department of Biology, College of Arts and Sciences, University of Wisconsin-Eau Claire, Eau Claire, WI, USA
| | - Mostafa Zamanian
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Lyric C Bartholomay
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Michael J Kimber
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
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Loghry HJ, Sondjaja NA, Minkler SJ, Kimber MJ. Secreted filarial nematode galectins modulate host immune cells. Front Immunol 2022; 13:952104. [PMID: 36032131 PMCID: PMC9402972 DOI: 10.3389/fimmu.2022.952104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/21/2022] [Indexed: 11/17/2022] Open
Abstract
Lymphatic filariasis (LF) is a mosquito-borne disease caused by filarial nematodes including Brugia malayi. Over 860 million people worldwide are infected or at risk of infection in 72 endemic countries. The absence of a protective vaccine means that current control strategies rely on mass drug administration programs that utilize inadequate drugs that cannot effectively kill adult parasites, thus established infections are incurable. Progress to address deficiencies in the approach to LF control is hindered by a poor mechanistic understanding of host-parasite interactions, including mechanisms of host immunomodulation by the parasite, a critical adaptation for establishing and maintaining infections. The canonical type 2 host response to helminth infection characterized by anti-inflammatory and regulatory immune phenotypes is modified by filarial nematodes during chronic LF. Current efforts at identifying parasite-derived factors driving this modification focus on parasite excretory-secretory products (ESP), including extracellular vesicles (EVs). We have previously profiled the cargo of B. malayi EVs and identified B. malayi galectin-1 and galectin-2 as among the most abundant EV proteins. In this study we further investigated the function of these proteins. Sequence analysis of the parasite galectins revealed highest homology to mammalian galectin-9 and functional characterization identified similar substrate affinities consistent with this designation. Immunological assays showed that Bma-LEC-2 is a bioactive protein that can polarize macrophages to an alternatively activated phenotype and selectively induce apoptosis in Th1 cells. Our data shows that an abundantly secreted parasite galectin is immunomodulatory and induces phenotypes consistent with the modified type 2 response characteristic of chronic LF infection.
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Wang Y, Ehsan M, Wang S, Tian X, Yan R, Song X, Xu L, Li X. Modulatory functions of recombinant electron transfer flavoprotein α subunit protein from Haemonchus contortus on goat immune cells in vitro. Vet Parasitol 2020; 288:109300. [PMID: 33152677 DOI: 10.1016/j.vetpar.2020.109300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/25/2020] [Accepted: 10/26/2020] [Indexed: 01/13/2023]
Abstract
Suppression and modulation of the host immune response to parasitic nematodes have been extensively studied. In the present study, we cloned and produced recombinant electron transfer flavoprotein α subunit (ETFα) protein from Haemonchus contortus (rHCETFα), a parasitic nematode of small ruminants, and studied the effect of this protein on modulating the immune response of goat peripheral blood mononuclear cells (PBMCs) and monocytes. Immunohistochemical tests verified that the HCETFα protein was localized mainly in the intestinal wall and on the body surface of worms. Immunoblot analysis revealed that rHCETFα was recognized by the serum of goats artificially infected with H. contortus. Immunofluorescence analysis indicated that rHCETFα bound to the surface of PBMCs. rHCETFα was co-incubated with goat PBMCs to observe the immunomodulatory effects exerted by HCETFα on proliferation, apoptosis, cytokine secretion and nitric oxide (NO) production. The results showed that rHCETFα suppressed the proliferation of goat PBMCs stimulated by concanavalin A and induced apoptosis in goat PBMCs. After rHCETFα exposure, IL-2, IL-4, IL-17A and TNF-α expression was markedly reduced, whereas secretion of TGF-β1 was significantly elevated, in goat PBMCs. Moreover, rHCETFα up-regulated NO production in a dose-dependent manner. FITC-dextran internalization assays showed that rHCETFα inhibited phagocytosis of goat monocytes. These results elucidate the interaction between parasites and hosts at the molecular level, suggest a possible immunomodulatory target and contribute to the search for innovative proteins that may be candidate targets for drugs and vaccines.
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Affiliation(s)
- Yujian Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China; School of Life Science, Huizhou University, Huizhou 516007, PR China.
| | - Muhammad Ehsan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Shuai Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Xiaowei Tian
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - RuoFeng Yan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - XiaoKai Song
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - LiXin Xu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - XiangRui Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
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Wang Y, Ehsan M, Huang J, Aimulajiang K, Yan R, Song X, Xu L, Li X. Characterization of a rhodanese homologue from Haemonchus contortus and its immune-modulatory effects on goat immune cells in vitro. Parasit Vectors 2020; 13:454. [PMID: 32894178 PMCID: PMC7487571 DOI: 10.1186/s13071-020-04333-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 08/31/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Modulation of the host immune response by nematode parasites has been widely reported. Rhodaneses (thiosulfate: cyanide sulfurtransferases) are present in a wide range of organisms, such as archaea, bacteria, fungi, plants and animals. Previously, it was reported that a rhodanese homologue could be bound by goat peripheral blood mononuclear cells (PBMCs) in vivo. METHODS In the present study, we cloned and produced a recombinant rhodanese protein originating from Haemonchus contortus (rHCRD), a parasitic nematode of small ruminants. rHCRD was co-incubated with goat PBMCs to assess its immunomodulatory effects on proliferation, apoptosis and cytokine secretion. RESULTS We verified that the natural HCRD protein localized predominantly to the bowel wall and body surface of the parasite. We further demonstrated that serum produced by goats artificially infected with H. contortus successfully recognized rHCRD, which bound to goat PBMCs. rHCRD suppressed proliferation of goat PBMCs stimulated by concanavalin A but did not induce apoptosis in goat PBMCs. The production of TNF-α and IFN-γ decreased significantly, whereas secretion of IL-10 and TGF-β1 increased, in goat PBMCs after exposure to rHCRD. rHCRD also inhibited phagocytosis by goat monocytes. Moreover, rHCRD downregulated the expression of major histocompatibility complex (MHC)-II on goat monocytes in a dose-dependent manner, but did not alter MHC-I expression. CONCLUSIONS These results propose a possible immunomodulatory target that may help illuminate the interactions between parasites and their hosts at the molecular level and reveal innovative protein species as candidate drug and vaccine targets.
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Affiliation(s)
- Yujian Wang
- School of Life Science, Huizhou University, Huizhou, 516007, People's Republic of China.,MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Muhammad Ehsan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Jianmei Huang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Kalibixiati Aimulajiang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - RuoFeng Yan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - XiaoKai Song
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - LiXin Xu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - XiangRui Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
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Characterization of a phosphotyrosyl phosphatase activator homologue of the parasitic nematode Haemonchus contortus and its immunomodulatory effect on goat peripheral blood mononuclear cells in vitro. Int J Parasitol 2020; 50:1157-1166. [PMID: 32866490 DOI: 10.1016/j.ijpara.2020.07.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/25/2020] [Accepted: 07/02/2020] [Indexed: 01/06/2023]
Abstract
Suppression and modulation of the host immune response to parasitic nematodes have been extensively studied. In the present study, we cloned and produced recombinant phosphotyrosyl phosphatase activator protein from Haemonchus contortus (rHCPTPA), a parasitic nematode of small ruminants, and studied the effect of this protein on modulating the immune response of goat peripheral blood mononuclear cells. Enzymatic assays revealed that rHCPTPA enhanced the p-nitrophenylphosphate phosphatase activity of bovine PP2A1. Immunohistochemical tests verified that the HCPTPA protein was localised mainly in the bowel wall and on the body surface of worms. It was also shown that serum produced by goats artificially infected with H. contortus successfully recognised rHCPTPA, which conjugated with goat peripheral blood mononuclear cells. The rHCPTPA was then co-incubated with goat peripheral blood mononuclear cells to assess its immunomodulatory effects on proliferation, apoptosis, cytokine secretion, migration and nitric oxide production. Our results showed that rHCPTPA suppressed the proliferation of goat peripheral blood mononuclear cells stimulated by concanavalin A and induced apoptosis in goat peripheral blood mononuclear cells. After rHCPTPA exposure, IFN-γ and IL-2 expression was markedly reduced, whereas secretion of IL-10 and IL-4 was significantly elevated, in goat peripheral blood mononuclear cells. Moreover, rHCPTPA down-regulated nitric oxide production and migration of goat peripheral blood mononuclear cells in a dose-dependent manner. These results illuminate the interaction between parasites and hosts at the molecular level, suggest a possible immunomodulatory target and contribute to the search for innovative proteins that might be candidate targets for drugs and vaccines.
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Abstract
During microbial infections, both innate and adaptive immunity are activated. Viruses and bacteria usually induce an acute inflammation in the first setting of infection, which helps the eliciting an effective immune response. In contrast, macroparasites such as helminths are a highly successful group of invaders known to be capable of maintaining a chronic infestation with the minimum instigation. Undoubtedly, generating such an immunoregulatory environment requires the exploitation of various immunosuppressive mechanisms to debilitate host immunity supporting their survival and replication. Several mechanisms have been recognized whereby helminths prolong their infections including an increase of immunoregulatory cells, inhibition of Th1 or Th2 responses, targeting pattern recognition receptors (PRRs) and lowering the immune cells quantity via induction of apoptosis. Apoptosis is a programmed intracellular process involving a series of consecutive downstream signalling event evolved to cell death. It plays a pivotal role in several immunological reactions in particular deletion of autoreactive immune cells. Helminth-triggered apoptosis in immune cells exhausts host immunity, which paves the way for generating a permissive environment and chronic infection. This review provides a compilation of recent investigations discussing the apoptotic mechanisms exploited by different worms and the immunological consequences of immune cell death. Finally, the anti-cancer effects of some worm-derived molecules due to their apoptotic effects are discussed, highlighting as potentially druggable candidates to combat cancer.
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Mishra R, Panda SK, Sahoo PK, Bal MS, Satapathy AK. Increased Fas ligand expression of peripheral B-1 cells correlated with CD4+T-cell apoptosis in filarial-infected patients. Parasite Immunol 2017; 39. [DOI: 10.1111/pim.12421] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 02/09/2017] [Indexed: 01/09/2023]
Affiliation(s)
- R. Mishra
- Regional Medical Research Centre (ICMR); Bhubaneswar Odisha India
| | - S. K. Panda
- Institutes of Life Sciences (DBT); Bhubaneswar Odisha India
| | - P. K. Sahoo
- Regional Medical Research Centre (ICMR); Bhubaneswar Odisha India
| | - M. S. Bal
- Regional Medical Research Centre (ICMR); Bhubaneswar Odisha India
| | - A. K. Satapathy
- Regional Medical Research Centre (ICMR); Bhubaneswar Odisha India
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Sanmarco LM, Visconti LM, Eberhardt N, Ramello MC, Ponce NE, Spitale NB, Vozza ML, Bernardi GA, Gea S, Minguez AR, Aoki MP. IL-6 Improves the Nitric Oxide-Induced Cytotoxic CD8+ T Cell Dysfunction in Human Chagas Disease. Front Immunol 2016; 7:626. [PMID: 28066435 PMCID: PMC5179535 DOI: 10.3389/fimmu.2016.00626] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 12/08/2016] [Indexed: 12/03/2022] Open
Abstract
Reactive oxygen and nitrogen species are important microbicidal agents and are also involved in lymphocyte unresponsiveness during experimental infections. Many of the biological effects attributed to nitric oxide are mediated by peroxynitrites, which induce the nitration of immune cells, among others. Our group has demonstrated that nitric oxide is involved in the suppressive activity of myeloid-derived suppressor cells in Trypanosoma cruzi-infected mice, with a higher number of CD8+ T cells suffering surface-nitration compared to uninfected controls. Studying the functional and phenotypic features of peripheral CD8+ T cells from chagasic patients and human cells experimentally infected with T. cruzi, we found that different regulatory mechanisms impaired the effector functions of T cytotoxic population from seropositive patients. Peripheral leukocytes from chagasic patients showed increased nitric oxide production concomitant with increased tyrosine nitration of CD8+ T cells. Additionally, this cytotoxic population exhibited increased apoptotic rate, loss of the TCRζ-chain, and lower levels of CD107a, a marker of degranulation. Strikingly, IL-6 stimulation of in vitro-infected peripheral blood mononuclear cells obtained from healthy donors, blunted T. cruzi-induced nitration of CD3+CD8+ cells, and increased their survival. Furthermore, the treatment of these cultures with an IL-6 neutralizing antibody increased the percentage of T. cruzi-induced CD8+ T cell nitration and raised the release of nitric oxide. The results suggest that the under-responsiveness of cytotoxic T cell population observed in the setting of long-term constant activation of the immune system could be reverted by the pleiotropic actions of IL-6, since this cytokine improves its survival and effector functions.
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Affiliation(s)
- Liliana Maria Sanmarco
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICET, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba , Argentina
| | | | - Natalia Eberhardt
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICET, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba , Argentina
| | - Maria Cecilia Ramello
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICET, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba , Argentina
| | - Nicolás Eric Ponce
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICET, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba , Argentina
| | | | - Maria Lola Vozza
- Hospital Nuestra Señora de la Misericordia del Nuevo Siglo , Córdoba , Argentina
| | | | - Susana Gea
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICET, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba , Argentina
| | - Angel Ramón Minguez
- Hospital Nuestra Señora de la Misericordia del Nuevo Siglo , Córdoba , Argentina
| | - Maria Pilar Aoki
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICET, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba , Argentina
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Babu S, Nutman TB. Immunology of lymphatic filariasis. Parasite Immunol 2014; 36:338-46. [PMID: 24134686 DOI: 10.1111/pim.12081] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 10/11/2013] [Indexed: 12/13/2022]
Abstract
The immune responses to filarial parasites encompass a complex network of innate and adaptive cells whose interaction with the parasite underlies a spectrum of clinical manifestations. The predominant immunological feature of lymphatic filariasis is an antigen-specific Th2 response and an expansion of IL-10 producing CD4(+) T cells that is accompanied by a muted Th1 response. This antigen-specific T-cell hyporesponsiveness appears to be crucial for the maintenance of the sustained, long-standing infection often with high parasite densities. While the correlates of protective immunity to lymphatic filariasis are still incompletely understood, primarily due to the lack of suitable animal models to study susceptibility, it is clear that T cells and to a certain extent B cells are required for protective immunity. Host immune responses, especially CD4(+) T-cell responses clearly play a role in mediating pathological manifestations of LF, including lymphedema, hydrocele and elephantiasis. The main underlying defect in the development of clinical pathology appears to be a failure to induce T-cell hyporesponsiveness in the face of antigenic stimulation. Finally, another intriguing feature of filarial infections is their propensity to induce bystander effects on a variety of immune responses, including responses to vaccinations, allergens and to other infectious agents. The complexity of the immune response to filarial infection therefore provides an important gateway to understanding the regulation of immune responses to chronic infections, in general.
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Affiliation(s)
- S Babu
- NIAID-NIRT-ICER, Chennai, India
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Metenou S, Coulibaly YI, Sturdevant D, Dolo H, Diallo AA, Soumaoro L, Coulibaly ME, Kanakabandi K, Porcella SF, Klion AD, Nutman TB. Highly heterogeneous, activated, and short-lived regulatory T cells during chronic filarial infection. Eur J Immunol 2014; 44:2036-47. [PMID: 24737144 DOI: 10.1002/eji.201444452] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/21/2014] [Accepted: 04/10/2014] [Indexed: 12/14/2022]
Abstract
The mechanisms underlying the increase in the numbers of regulatory T (Treg) cells in chronic infection settings remain unclear. Here we have delineated the phenotype and transcriptional profiles of Treg cells from 18 filarial-infected (Fil(+) ) and 19 filarial-uninfected (Fil(-) ) subjects. We found that the frequencies of Foxp3(+) Treg cells expressing CTLA-4, GITR, LAG-3, and IL-10 were significantly higher in Fil(+) subjects compared with that in Fil(-) subjects. Foxp3-expressing Treg-cell populations in Fil(+) subjects were also more heterogeneous and had higher expression of IL-10, CCL-4, IL-29, CTLA-4, and TGF-β than Fil(-) subjects, each of these cytokines having been implicated in immune suppression. Moreover, Foxp3-expressing Treg cells from Fil(+) subjects had markedly upregulated expression of activation-induced apoptotic genes with concomitant downregulation of those involved in cell survival. To determine whether the expression of apoptotic genes was due to Treg-cell activation, we found that the expression of CTLA-4, CDk8, RAD50, TNFRSF1A, FOXO3, and RHOA were significantly upregulated in stimulated cells compared with unstimulated cells. Taken together, our results suggest that in patent filarial infection, the expanded Treg-cell populations are heterogeneous, short-lived, activated, and express higher levels of molecules known to modulate immune responsiveness, suggesting that filarial infection is associated with high Treg-cell turnover.
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Affiliation(s)
- Simon Metenou
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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Das Mohapatra A, Panda SK, Pradhan AK, Prusty BK, Satapathy AK, Ravindran B. Filarial antigens mediate apoptosis of human monocytes through Toll-like receptor 4. J Infect Dis 2014; 210:1133-44. [PMID: 24737802 DOI: 10.1093/infdis/jiu208] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Apoptosis of several host cells induced by parasites/parasite products has been investigated in human filariasis to understand immune hyporesponsiveness. However, apoptosis of monocytes-one of the major antigen presenting cells in peripheral circulation, which are chronically exposed to filarial antigens in infected subjects-is yet to be understood. METHODS Apoptosis of human monocytes with Brugia pahangi antigen (BpA) was demonstrated by scoring several apoptotic markers using flow cytometry. Ability of BpA and plasma of infected subjects to suppress lymphocyte proliferation was demonstrated by (3)H thymidine incorporation assay and carboxyfluorescein succinimidyl ester dilution assay. RESULTS BpA induced significant apoptosis of normal human monocytes, primarily through Toll-like receptor 4 (TLR4), and suppressed phytohemagglutinin (PHA)-mediated proliferation of normal human T lymphocytes. However, monocytes of Wuchereria bancrofti-infected subjects were resistant to BpA-induced apoptosis. Plasma of infected subjects also mediated apoptosis of normal monocytes, presumably due to circulating filarial antigens, and resulted in inhibition of PHA-induced proliferation. CONCLUSION Normal human monocytes were found to be qualitatively different from those of filariasis-infected subjects; whereas filarial antigens mediate apoptosis of normal human monocytes through TLR4, those of infected subjects were found to be resistant.
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Affiliation(s)
| | | | | | | | - Ashok Kumar Satapathy
- Department of Immunology, Regional Medical Research Center, Indian Council of Medical Research, Bhubaneswar, India
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Kushwaha S, Singh PK, Rana AK, Misra-Bhattacharya S. Immunization of Mastomys coucha with Brugia malayi recombinant trehalose-6-phosphate phosphatase results in significant protection against homologous challenge infection. PLoS One 2013; 8:e72585. [PMID: 24015262 PMCID: PMC3755969 DOI: 10.1371/journal.pone.0072585] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 07/18/2013] [Indexed: 11/19/2022] Open
Abstract
Development of a vaccine to prevent or reduce parasite development in lymphatic filariasis would be a complementary approach to existing chemotherapeutic tools. Trehalose-6-phosphate phosphatase of Brugia malayi (Bm-TPP) represents an attractive vaccine target due to its absence in mammals, prevalence in the major life stages of the parasite and immunoreactivity with human bancroftian antibodies, especially from endemic normal subjects. We have recently reported on the cloning, expression, purification and biochemical characterization of this vital enzyme of B. malayi. In the present study, immunoprophylactic evaluation of Bm-TPP was carried out against B. malayi larval challenge in a susceptible host Mastomys coucha and the protective ability of the recombinant protein was evaluated by observing the adverse effects on microfilarial density and adult worm establishment. Immunization caused 78.4% decrease in microfilaremia and 71.04% reduction in the adult worm establishment along with sterilization of 70.06% of the recovered live females. The recombinant protein elicited a mixed Th1/Th2 type of protective immune response as evidenced by the generation of both pro- and anti-inflammatory cytokines IL-2, IFN-γ, TNF-α, IL-4 and an increased production of antibody isotypes IgG1, IgG2a, IgG2b and IgA. Thus immunization with Bm-TPP conferred considerable protection against B. malayi establishment by engendering a long-lasting effective immune response and therefore emerges as a potential vaccine candidate against lymphatic filariasis (LF).
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Affiliation(s)
- Susheela Kushwaha
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
| | - Prashant Kumar Singh
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
| | - Ajay Kumar Rana
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
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Othman AA, Ashour DS, Mohamed DA. Toxocara-induced hepatic inflammation: Immunohistochemical characterization of lymphocyte subpopulations and Bcl-2 expression. Exp Parasitol 2013; 134:76-81. [DOI: 10.1016/j.exppara.2013.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 01/30/2013] [Accepted: 02/04/2013] [Indexed: 11/25/2022]
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Semnani RT. The interaction between filarial parasites and human monocyte/macrophage populations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 785:49-56. [PMID: 23456837 DOI: 10.1007/978-1-4614-6217-0_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lymphatic filariasis is a mafor tropical disease affecting approximately 120 million people worldwide. Patent infection, by and large, is clinically asymptomatic but is associated with the inability of T cells to proliferate or produce IFN-γ in response to parasite antigen. Monocyte dysfunction is one hypothesis felt to explain the lack of an antigen-specific T cell response. In fact, monocytes from filaria-infected individuals have been shown to be studded with internalized filarial antigens. Understanding how the phenotype and the function of these monocytes are altered through the internalization of these parasite antigens is one of the areas our laboratory has focused on. In fact, the existence and/or function of alternatively activated macrophages in murine models of filarial infections have been extensively studied. Whether this population of macrophages can be induced in human filarial infections is the main focus of this review.
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Affiliation(s)
- Roshanak Tolouei Semnani
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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15
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Prednisolone and cyclosporine A: Effects on an experimental model of ancylostomiasis. Exp Parasitol 2013; 133:80-8. [PMID: 23142084 DOI: 10.1016/j.exppara.2012.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 09/20/2012] [Accepted: 10/19/2012] [Indexed: 10/27/2022]
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Immunopathogenesis of lymphatic filarial disease. Semin Immunopathol 2012; 34:847-61. [PMID: 23053393 DOI: 10.1007/s00281-012-0346-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 09/13/2012] [Indexed: 01/06/2023]
Abstract
Although two thirds of the 120 million people infected with lymph-dwelling filarial parasites have subclinical infections, ~40 million have lymphedema and/or other pathologic manifestations including hydroceles (and other forms of urogenital disease), episodic adenolymphangitis, tropical pulmonary eosinophilia, lymphedema, and (in its most severe form) elephantiasis. Adult filarial worms reside in the lymphatics and lymph nodes and induce changes that result in dilatation of lymphatics and thickening of the lymphatic vessel walls. Progressive lymphatic damage and pathology results from the summation of the effect of tissue alterations induced by both living and nonliving adult parasites, the host inflammatory response to the parasites and their secreted antigens, the host inflammatory response to the endosymbiont Wolbachia, and those seen as a consequence of secondary bacterial or fungal infections. Inflammatory damage induced by filarial parasites appears to be multifactorial, with endogenous parasite products, Wolbachia, and host immunity all playing important roles. This review will initially examine the prototypical immune responses engendered by the parasite and delineate the regulatory mechanisms elicited to prevent immune-mediated pathology. This will be followed by a discussion of the proposed mechanisms underlying pathogenesis, with the central theme being that pathogenesis is a two-step process-the first initiated by the parasite and host innate immune system and the second propagated mainly by the host's adaptive immune system and by other factors (including secondary infections).
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Cho BA, Ko Y, Kim YS, Kim S, Choi MS, Kim IS, Kim HR, Cho NH. Phenotypic characterization of peripheral T cells and their dynamics in scrub typhus patients. PLoS Negl Trop Dis 2012; 6:e1789. [PMID: 22905277 PMCID: PMC3419201 DOI: 10.1371/journal.pntd.0001789] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 07/10/2012] [Indexed: 11/26/2022] Open
Abstract
Background Scrub typhus, caused by Orientia tsutsugamushi infection, is one of the main causes of febrile illness in the Asia-Pacific region. Although cell-mediated immunity plays an important role in protection, little is known about the phenotypic changes and dynamics of leukocytes in scrub typhus patients. Methodology/Principal Findings To reveal the underlying mechanisms of immunological pathogenesis, we extensively analyzed peripheral blood leukocytes, especially T cells, during acute and convalescent phases of infection in human patients and compared with healthy volunteers. We observed neutrophilia and CD4+ T lymphopenia in the acute phase of infection, followed by proliferation of CD8+ T cells during the convalescent phase. Massive T cell apoptosis was detected in the acute phase and preferential increase of CD8+ T cells with activated phenotypes was observed in both acute and convalescent phases, which might be associated or correlated with elevated serum IL-7 and IL-15. Interestingly, peripheral Treg cells were significantly down-regulated throughout the disease course. Conclusions/Significance The remarkable decrease of CD4+ T cells, including Treg cells, during the acute phase of infection may contribute to the loss of immunological memory that are often observed in vaccine studies and recurrent human infection. Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi infection. It has been estimated that one billion people are at risk and one million new cases arise each year in Asian-pacific region. Despite of aggressive attempts to develop a prophylactic vaccine against scrub typhus during the last several decades, all approaches have failed to generate long lasting immunity. In addition, little is known about the immunological pathogenesis of scrub typhus. To understand the pathogenic mechanisms of this infectious disease, we extensively analyzed peripheral leukocytes, especially T cells, in Korean scrub typhus patients and compared with healthy volunteers. We observed neutrophilia and CD4+/T lymphopenia in the acute phase of infection, followed by proliferation of CD8+ T cells during the convalescent phase. Massive T cell apoptosis was detected in the acute phase and a preferential increase of CD8+ T cells with activated phenotypes was observed in both acute and convalescent phases. The remarkable decrease of CD4+ T cells, including Treg cells, during the acute phase of infection may contribute to the loss of immunological memory and generate helpless but unregulated cytotoxic T cell responses observed in vaccine studies and recurrent human infection.
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Affiliation(s)
- Bon-A Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Anatomy, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Endemic Disease, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Youngho Ko
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yeon-Sook Kim
- Divisions of Infectious Diseases, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Sanguk Kim
- Department of Life Science and School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, Kyungbuk, Republic of Korea
| | - Myung-Sik Choi
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ik-Sang Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hang-Rae Kim
- Department of Anatomy, Seoul National University College of Medicine, Seoul, Republic of Korea
- * E-mail: (NHC); (HRK)
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Endemic Disease, Seoul National University Medical Research Center, Seoul, Republic of Korea
- Bundang Hospital, Seoul, Republic of Korea
- * E-mail: (NHC); (HRK)
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Relationship between pro-and anti-inflammatory cytokines profiles and some haematological parameters in some Cameroonians infected with Onchocerca volvulus. ASIAN PAC J TROP MED 2012; 5:713-7. [PMID: 22805723 DOI: 10.1016/s1995-7645(12)60112-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 05/15/2012] [Accepted: 07/15/2012] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE To investigate the relationship between white blood cells, lymphocytes, monocytes, and Interleukin(IL)-1 α, IL-6, IL-10 and IL-13 production in Cameroonians with Onchocerca volvulus (O. volvulus) infection. METHODS A total of 357 individuals from five sites at Upper Sanga, Lekkie, Nyong, Kelle and Sanaga Maritime divisions and located along Sanaga valley of Sanaga River in South Cameroon were screened for the presence of O. volvulus using the skin snip. The levels of the interleukins (IL-) namely IL-1 α, IL-6, IL-10 and IL-13 were evaluated using enzyme linked immunoabsorbent assay techniques. Haematological parameters were evaluated using standard laboratory automated analyser. RESULTS O. volvulus microfilariae were found in skin tissues of 85 (23.81%) volunteers. The mean interleukin (IL-) levels in the O. volvulus control and infected individuals were IL-1 α in (1.65 ± 0.79 and 2.31 ± 0.5) pg/mL; IL-6 in (278.36 ± 55.34 and 201.74 ± 34.56) pg/mL; IL-10 in (436.03 ± 208.64 and 418.49 ± 147.88) pg/mL and IL-13 in (8.98 ± 7.28 and 38.06 ± 11.92) pg/mL. There was a negative correlation between monocyte counts and IL-10 concentration in positive individuals. A negative correlation of IL-6 with white blood cell and lymphocyte counts was observed (P<0.05). The level of IL-13 was positively associated with microfilarial load (P<0.05). CONCLUSIONS We observed depressed IL-6 and raised IL-13 concentrations in the sera of individuals with onchocerciasis which implicate these interleukins in the immunological responses of the disease. Therefore, these IL-6 and IL-13 are associated with O. volvulus infection among Cameroonians.
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Sreenivas K, Vijayan K, Babu S, Narayanan RB. Recombinant Brugia malayi pepsin inhibitor (rBm33) induced monocyte function and absence of apoptotic cell death: an in vitro study. Microb Pathog 2012; 53:19-27. [PMID: 22484090 PMCID: PMC3512105 DOI: 10.1016/j.micpath.2012.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 03/19/2012] [Accepted: 03/26/2012] [Indexed: 10/28/2022]
Abstract
The effect of recombinant Brugia malayi pepsin inhibitor (rBm33) on human monocytes/macrophages has been examined using THP-1 cells. THP-1 cells stimulated with rBm33 showed enhanced levels of expression of pro-inflammatory cytokines (IL-1β, TNF-α, IL-6) and diminished levels of IL-12, iNOS and anti-inflammatory cytokine (IL-10) expression suggesting the predominant features of Th1 response. Phorbol-12-myristate-13-acetate (PMA) treated THP-1 cells stimulated with rBm33 and subsequent incubation with GFP expressing Escherichia coli (E. coli) for 2 h enhanced the uptake of E. coli. Nitric oxide (NO) levels measured in the supernatants of these cultures did not show significant changes. Apoptotic studies with Peripheral Blood Mononuclear Cells (PBMCs) from normal individuals stimulated with rBm33 did not induce apoptosis of monocytes or lymphocytes. These observations suggest that rBm33 stimulates macrophages to induce Th1 response and does not promote apoptosis.
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Affiliation(s)
- Kirthika Sreenivas
- Centre for Biotechnology, Anna University, S.P road, Guindy, Chennai, Tamil Nadu 600025, India
| | - Kamalakannan Vijayan
- Centre for Biotechnology, Anna University, S.P road, Guindy, Chennai, Tamil Nadu 600025, India
| | - Subash Babu
- NIH-TRC-ICER SAIC-Frederick Inc, National Cancer Institute at Frederick, Chetpet, Chennai, India
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20
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Mladineo I, Petrić M, Hrabar J, Bočina I, Peharda M. Reaction of the mussel Mytilus galloprovincialis (Bivalvia) to Eugymnanthea inquilina (Cnidaria) and Urastoma cyprinae (Turbellaria) concurrent infestation. J Invertebr Pathol 2012; 110:118-25. [DOI: 10.1016/j.jip.2012.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 03/02/2012] [Accepted: 03/05/2012] [Indexed: 11/29/2022]
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21
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Steel C, Varma S, Nutman TB. Regulation of global gene expression in human Loa loa infection is a function of chronicity. PLoS Negl Trop Dis 2012; 6:e1527. [PMID: 22389737 PMCID: PMC3289604 DOI: 10.1371/journal.pntd.0001527] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 01/01/2012] [Indexed: 01/22/2023] Open
Abstract
Background Human filarial infection is characterized by downregulated parasite-antigen specific T cell responses but distinct differences exist between patients with longstanding infection (endemics) and those who acquired infection through temporary residency or visits to filarial-endemic regions (expatriates). Methods and Findings To characterize mechanisms underlying differences in T cells, analysis of global gene expression using human spotted microarrays was conducted on CD4+ and CD8+ T cells from microfilaremic Loa loa-infected endemic and expatriate patients. Assessment of unstimulated cells showed overexpression of genes linked to inflammation and caspase-associated cell death, particularly in endemics, and enrichment of the Th1/Th2 canonical pathway in endemic CD4+ cells. However, pathways within CD8+ unstimulated cells were most significantly enriched in both patient groups. Antigen (Ag)-driven gene expression was assessed to microfilarial Ag (MfAg) and to the nonparasite Ag streptolysin O (SLO). For MfAg-driven cells, the number of genes differing significantly from unstimulated cells was greater in endemics compared to expatriates (p<0.0001). Functional analysis showed a differential increase in genes associated with NFkB (both groups) and caspase activation (endemics). While the expatriate response to MfAg was primarily a CD4+ pro-inflammatory one, the endemic response included CD4+ and CD8+ cells and was linked to insulin signaling, histone complexes, and ubiquitination. Unlike the enrichment of canonical pathways in CD8+ unstimulated cells, both groups showed pathway enrichment in CD4+ cells to MfAg. Contrasting with the divergent responses to MfAg seen between endemics and expatriates, the CD4+ response to SLO was similar; however, CD8+ cells differed strongly in the nature and numbers (156 [endemics] vs 36 [expatriates]) of genes with differential expression. Conclusions These data suggest several important pathways are responsible for the different outcomes seen among filarial-infected patients with varying levels of chronicity and imply an important role for CD8+ cells in some of the global changes seen with lifelong exposure. Infection with the filarial parasite Loa loa causes a parasite-specific downregulation of T cell responses. However, differences exist (clinical and immunologic) between patients born and living in filarial endemic regions (endemics) and those who become infected during travel or short-term residency (expatriates). T cell responses are more depressed in endemics while expatriates have more clinical “allergic-type” symptoms. In this study, we showed that these differences reflect transcriptional differences within the T cell compartment. Using microarrays, we examined global gene expression in both CD4+ and CD8+ T cells of microfilaremic endemic and expatriate patients and found differences not only ex vivo, but also to parasite and, for CD8+ cells, to nonparasite antigens. Functional analysis showed that endemic patients expressed genes linked to inflammatory disease and caspase associated cell death at homeostasis while expatriates tended to have a more activation-induced gene profile at homeostasis and a CD4+ inflammatory response to parasite antigen. Patient groups were similar in their CD4+ response to nonparasite antigen but strongly differed in their CD8+ responses, demonstrating the potential global ramifications of chronic, longstanding infection. Our study describes potential transcriptional mechanisms for the variability seen in patients with different levels of exposure to and chronicity of filarial infection.
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Affiliation(s)
- Cathy Steel
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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22
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Cançado GGL, Fiuza JA, de Paiva NCN, Lemos LDCD, Ricci ND, Gazzinelli-Guimarães PH, Martins VG, Bartholomeu DC, Negrão-Corrêa DA, Carneiro CM, Fujiwara RT. Hookworm products ameliorate dextran sodium sulfate-induced colitis in BALB/c mice. Inflamm Bowel Dis 2011; 17:2275-86. [PMID: 21290484 DOI: 10.1002/ibd.21629] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 12/08/2010] [Indexed: 12/26/2022]
Abstract
BACKGROUND Several lines of evidence have shown that helminthiasis can significantly reduce disease severity in animal models of intestinal inflammation, airway inflammation/hyperreactivity, diabetes, and multiple sclerosis. Identification and characterization of helminth-derived immunomodulatory molecules that contribute to anticolitis effects could lead to new therapeutic approaches in inflammatory bowel diseases (IBDs) without the need for helminth infection. We evaluated the therapeutic potential of adult human hookworm, Ancylostoma ceylanicum, crude (Aw) and excreted/secreted (ES) products on dextran sulfate sodium (DSS)-induced colitis in BALB/c mice. METHODS Colitis was induced by 5% DSS oral administration for 7 days. Clinical disease severity was monitored daily during concomitant intraperitoneal treatment with helminth-derived products. Additionally, several pathways of immunological modulation induced by A. ceylanicum products (MPO, EPO, Th1, Th2, and Th17 cytokine responses) in the inflamed intestinal microenvironment were assessed. Finally, the histopathological profile of the colon was characterized. RESULTS Hookworm products are able to modulate the potent proinflammatory response induced by DSS, mainly through the downregulation of Th1 and Th17 cytokines. These proteins also reduce clinical and colonic microscopic inflammation scores as well as EPO and MPO activity. CONCLUSIONS Ancylostoma ceylanicum Aw and ES mediators have an important therapeutic potential in experimental colitis in mice, which may provide a more socially acceptable form of therapy for patients with IBDs as opposed to using living worms. Our results support the urgency of further isolation and recombinant expression of active hookworm products responsible for the beneficial effects on colitis.
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Altered T cell memory and effector cell development in chronic lymphatic filarial infection that is independent of persistent parasite antigen. PLoS One 2011; 6:e19197. [PMID: 21559422 PMCID: PMC3084782 DOI: 10.1371/journal.pone.0019197] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 03/22/2011] [Indexed: 02/08/2023] Open
Abstract
Chronic lymphatic filarial (LF) infection is associated with suppression of parasite-specific T cell responses that persist even following elimination of infection. While several mechanisms have been implicated in mediating this T cell specific downregulation, a role for alterations in the homeostasis of T effector and memory cell populations has not been explored. Using multiparameter flow cytometry, we investigated the role of persistent filarial infection on the maintenance of T cell memory in patients from the filarial-endemic Cook Islands. Compared to filarial-uninfected endemic normals (EN), microfilaria (mf) positive infected patients (Inf) had a reduced CD4 central memory (TCM) compartment. In addition, Inf patients tended to have more effector memory cells (TEM) and fewer effector cells (TEFF) than did ENs giving significantly smaller TEFF ∶ TEM ratios. These contracted TCM and TEFF populations were still evident in patients previously mf+ who had cleared their infection (CLInf). Moreover, the density of IL-7Rα, necessary for T memory cell maintenance (but decreased in T effector cells), was significantly higher on memory cells of Inf and CLInf patients, although there was no evidence for decreased IL-7 or increased soluble IL7-Rα, both possible mechanisms for signaling defects in memory cells. However, effector cells that were present in Inf and CLInf patients had lower percentages of HLA-DR suggesting impaired function. These changes in T cell populations appear to reflect chronicity of infection, as filarial-infected children, despite the presence of active infection, did not show alterations in the frequencies of these T cell phenotypes. These data indicate that filarial-infected patients have contracted TCM compartments and a defect in effector cell development, defects that persist even following clearance of infection. The fact that these global changes in memory and effector cell compartments do not yet occur in infected children makes early treatment of LF even more crucial.
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Krushna NSA, Shiny C, Manokaran G, Elango S, Babu S, Narayanan RB. Immune responses to recombinant Brugia malayi pepsin inhibitor homolog (Bm-33) in patients with human lymphatic filariaisis. Parasitol Res 2011; 108:407-15. [PMID: 20927633 PMCID: PMC3515686 DOI: 10.1007/s00436-010-2081-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 09/08/2010] [Indexed: 10/19/2022]
Abstract
Immune responses to recombinant Brugia malayi pepsin inhibitor homolog (rBm-33) were investigated in patients with human lymphatic filariasis (microfilaremics (MF) and chronic pathology (CP)) along with endemic normals (EN). Flow cytometric analysis (24 h) revealed CD4(+) T cell activation in patients (MF and CP) compared to normals (EN), with increased expression of CD69 and diminished levels of CD62L and CD127. This was associated with an elevated expression of CD154 but not CD28 and CTLA4 in CP patients. However, Bm-33-induced cytokine expression profile (IL-1β, IL-12, IL-8, IFN-γ, IL-10 and TGF-β) did not exhibit any significant difference between normals and patients at the same time point. Although CD4(+) T cell activation was observed initially in filarial patients (24 h), lymphoproliferation studies (96 h) suggested diminished proliferation compared to normals, indicating functional inactivation in the former upon prolonged antigen exposure. This indicates that rBm-33 induces an early T cell activation in MF and CP patients followed by a decreased lymphoproliferation that might contribute to immune suppression in these individuals.
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MESH Headings
- Animals
- Antibodies, Helminth/blood
- Antigens, Helminth/immunology
- Antigens, Helminth/therapeutic use
- Brugia malayi/immunology
- Cell Proliferation/drug effects
- Cells, Cultured
- Cytokines/genetics
- Cytokines/metabolism
- DNA, Complementary/biosynthesis
- DNA, Complementary/genetics
- DNA, Complementary/metabolism
- Elephantiasis, Filarial/blood
- Elephantiasis, Filarial/drug therapy
- Elephantiasis, Filarial/immunology
- Gene Expression Regulation/drug effects
- Helminth Proteins/immunology
- Helminth Proteins/therapeutic use
- Humans
- Immunity, Cellular/drug effects
- Immunity, Cellular/immunology
- Immunologic Factors/immunology
- Immunologic Factors/therapeutic use
- Leukocytes, Mononuclear/drug effects
- Leukocytes, Mononuclear/immunology
- Lymphocyte Activation/drug effects
- Lymphocyte Activation/immunology
- Recombinant Proteins/immunology
- Reverse Transcriptase Polymerase Chain Reaction
- T-Lymphocytes/drug effects
- T-Lymphocytes/immunology
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Affiliation(s)
- N. S. A. Krushna
- Centre for Biotechnology, Anna University, Guindy, Chennai 600025, India
| | - C. Shiny
- Centre for Biotechnology, Anna University, Guindy, Chennai 600025, India
| | - G. Manokaran
- Apollo Hospital, Greams Road, Chennai 600 006, India
| | - S. Elango
- Department of Public Health and Preventive Medicine, Government of Tamil Nadu, Chennai 600 006, India
| | - S. Babu
- NIH-TRC-ICER SAIC-Frederick Inc., National Cancer Institute at Frederick, Chetpet, Chennai 600 003, India
| | - R. B. Narayanan
- Centre for Biotechnology, Anna University, Guindy, Chennai 600025, India
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25
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Anaplasma marginale infection with persistent high-load bacteremia induces a dysfunctional memory CD4+ T lymphocyte response but sustained high IgG titers. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:1881-90. [PMID: 20943884 DOI: 10.1128/cvi.00257-10] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Control of blood-borne infections is dependent on antigen-specific effector and memory T cells and high-affinity IgG responses. In chronic infections characterized by a high antigen load, it has been shown that antigen-specific T and B cells are vulnerable to downregulation and apoptosis. Anaplasma marginale is a persistent infection of cattle characterized by acute and chronic high-load bacteremia. We previously showed that CD4(+) T cells primed by immunization with an A. marginale outer membrane protein were rapidly deleted following infection. Furthermore, peripheral blood T cell responses to bacteria were not observed after acute infection was controlled, suggesting dysfunctional T cell priming to other A. marginale antigens. The current study more closely investigated the kinetics of A. marginale-specific CD4(+) T cell responses primed during infection. Frequent sampling of peripheral blood and spleens revealed that antigen-specific CD4(+) T cell responses were first detected at 5 to 7 weeks, but the responses were sporadic and transient thereafter. A similar pattern was observed in animals sampled weekly for nearly 1 year. Paradoxically, by 2 weeks of infection, cattle had developed high titers of A. marginale-specific IgG, which remained high throughout persistent infection. This dysfunctional CD4(+) T cell response to infection is consistent with continual downregulation or deletion of newly primed effector T cells, similar to what was observed for immunization-induced T cells following A. marginale infection. The failure to establish a strong memory T cell response during A. marginale infection likely contributes to bacterial persistence.
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26
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Dondji B, Sun T, Bungiro RD, Vermeire JJ, Harrison LM, Bifulco C, Cappello M. CD4 T cells mediate mucosal and systemic immune responses to experimental hookworm infection. Parasite Immunol 2010; 32:406-13. [PMID: 20500671 DOI: 10.1111/j.1365-3024.2010.01204.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Hookworm infection is associated with anaemia and malnutrition in many resource-limited countries. Ancylostoma hookworms have previously been shown to modulate host cellular immune responses through multiple mechanisms, including reduced mitogen-mediated lymphocyte proliferation, impaired antigen presentation/processing, and relative reductions in CD4(+) T cells in the spleen and mesenteric lymph nodes. Syrian hamsters were depleted of CD4(+) for up to 9 days following intraperitoneal injection (200 microg) of a murine anti-mouse CD4 monoclonal IgG (clone GK1.5). CD4(+) T-cell-depleted hamsters infected with the hookworm Ancylostoma ceylanicum exhibited a threefold higher mean intestinal worm burden and more severe anaemia than animals that received isotype control IgG. In addition, depletion of CD4(+) T cells was associated with impaired cellular and humoral (serum and mucosal) immune responses to hookworm antigens. These data demonstrate an effector role for CD4(+) T cells in hookworm immunity and disease pathogenesis. Ultimately, these studies may yield important insights into the relationship between intestinal nematode infections and diseases that are associated with CD4(+) T-cell depletion, including HIV.
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Affiliation(s)
- B Dondji
- Program in International Child Health, Department of Pediatrics, Yale University School of Medicine, New Haven CT, USA
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27
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Nitric oxide and respiratory helminthic diseases. J Biomed Biotechnol 2010; 2010:958108. [PMID: 20169170 PMCID: PMC2821625 DOI: 10.1155/2010/958108] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 10/12/2009] [Indexed: 11/17/2022] Open
Abstract
Nitric oxide (NO) is a very simple molecule that displays very important functions both in helminths (mainly those involved in respiratory pathology) and in mammalian hosts. In this paper we review four issues related to interaction of NO and lung helminthic diseases. Firstly, we evaluated data available on the NO synthesis and release by helminths and their biological role. Next, we summarized the effect of antigens obtained from different phases of the biological cycle on NO production by host mammalian cells (mainly from human sources). Thirdly, we revised the evaluation of NO on the biological activities and/or the viability of respiratory helminths. Lastly, the deleterious consequences of increased production of NO during helminthic human infection are detailed.
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Venugopal PG, Nutman TB, Semnani RT. Activation and regulation of toll-like receptors (TLRs) by helminth parasites. Immunol Res 2009; 43:252-63. [PMID: 18982454 DOI: 10.1007/s12026-008-8079-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Helminth (worm) infections are major public health problems that have important socioeconomic consequences for the more than 2 billion infected individuals. Chronicity (their hallmark) can lead to anemia (in hookworm infection), river blindness (onchcerciasis), cirrhosis (schistosomiasis), and elephantiasis (lymphatic filariasis). Although there have been many studies examining innate immune responses (including TLR expression and function) in response to intracellular pathogens, fewer have examined the interaction of the multicellular helminth parasites and the innate immune system. This review will focus on two "systemic" helminth parasitic infections (lymphatic filariasis and schistosomiasis) and the regulation of TLRs that may contribute to infection outcome.
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Affiliation(s)
- Priyanka Goel Venugopal
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 4 Center Drive, Room 126, Bethesda, MD 20892-0425, USA
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Toubarro D, Lucena-Robles M, Nascimento G, Costa G, Montiel R, Coelho AV, Simões N. An apoptosis-inducing serine protease secreted by the entomopathogenic nematode Steinernema carpocapsae. Int J Parasitol 2009; 39:1319-30. [PMID: 19481087 DOI: 10.1016/j.ijpara.2009.04.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 04/09/2009] [Accepted: 04/14/2009] [Indexed: 11/26/2022]
Abstract
Steinernema carpocapsae is an insect parasitic nematode able to parasitise and kill the host within 48 h. Secreted products (ESP) of the parasitic stage of a virulent strain contain higher amounts of proteolytic activity than a low virulence strain, suggesting proteases are involved in virulence. From the ESP we purified a protein (Sc-SP-3) with a M(r) of 30 kDa and a pI of 7 that cleaved the synthetic substrate N-succinyl-Ala-Ala-Pro-Phe-pNA and was inhibited by phenylmethanesulfonyl fluoride, benzamidine and chymostatin, thus indicating that it belongs to the chymotrypsin-like serine protease family. Sc-SP-3 has a V(max) of 0.3 mM min(-1)ml(-1) and K(m) of 6.6 x 10(-4)M, with maximum activity at pH 8 and 40 degrees C. The full-length cDNA was obtained using degenerate oligonucleotides for serine proteases. This open reading frame encodes a preproprotein containing a putative signal peptide composed of 16 amino acid residues, a prodomain of 40 residues and a mature protease domain of 261 residues, including the catalytic triad His/Asp/Ser characteristic of trypsin-like serine proteases. The N-terminal sequence and the peptide masses fingerprint obtained by MALDI-TOF-MS for the purified protein matched the cDNA. Gene expression analysis by quantitative real-time-PCR showed that this gene is expressed only during the parasitic stage and that pre-invasive nematodes inside the mid-gut expressed higher amounts of Sc-SP-3 than those that already enter the haemocoel. Sc-SP-3 caused histolysis in the insect mid-gut. In vitro assays demonstrated that Sc-SP-3 digested extracellular proteins and induced apoptosis in Sf9 insect cells, thus suggesting Sc-SP-3 is a multifunctional chymotrypsin-like protease involved in pathogenesis.
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Affiliation(s)
- Duarte Toubarro
- CIRN, Departamento de Biologia, Universidade dos Açores, Apartado 1422, 9501-801 Ponta Delgada, Portugal
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30
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Fujiwara RT, Cançado GGL, Freitas PA, Santiago HC, Massara CL, Carvalho ODS, Corrêa-Oliveira R, Geiger SM, Bethony J. Necator americanus infection: a possible cause of altered dendritic cell differentiation and eosinophil profile in chronically infected individuals. PLoS Negl Trop Dis 2009; 3:e399. [PMID: 19308259 PMCID: PMC2654967 DOI: 10.1371/journal.pntd.0000399] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 02/26/2009] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Hookworms survive for several years (5 to 7 years) in the host lumen, inducing a robust but largely ineffective immune response. Among the most striking aspects of the immune response to hookworm (as with many other helminths) is the ablation of parasite-specific T cell proliferative response (hyporesponsiveness). While the role of the adaptive immune response in human helminth infection has been well investigated, the role of the innate immune responses (e.g., dendritic cells and eosinophils) has received less attention and remains to be clearly elucidated. METHODOLOGY/PRINCIPAL FINDINGS We report on the differentiation/maturation of host dendritic cells in vitro and the eosinophil activation/function associated with human hookworm infection. Mature DCs (mDCs) from Necator americanus (Necator)-infected individuals showed an impaired differentiation process compared to the mDCs of non-infected individuals, as evidenced by the differential expression of CD11c and CD14. These same hookworm-infected individuals also presented significantly down-regulated expression of CD86, CD1a, HLA-ABC, and HLA-DR. The lower expression of co-stimulatory and antigen presentation molecules by hookworm-infected-derived mDCs was further evidenced by their reduced ability to induce cell proliferation. We also showed that this alternative DC differentiation is partially induced by excreted-secreted hookworm products. Conversely, eosinophils from the same individuals showed a highly activated status, with an upregulation of major cell surface markers. Antigen-pulsed eosinophils from N. americanus-infected individuals induced significant cell proliferation of autologous PBMCs, when compared to non-infected individuals. CONCLUSION Chronic N. americanus infection alters the host's innate immune response, resulting in a possible modulation of the maturation process of DCs, a functional change that may diminish their ability for antigen presentation and thus contribute to the ablation of the parasite-specific T cell proliferative response. Interestingly, a concomitant upregulation of the major cell surface markers of eosinophils was observed in hookworm-infected individuals, indicative of antigen-specific immune responses, especially antigen presentation. We showed that in addition to the postulated role of the eosinophils as effector cells against helminth infection, activated cells may also be recruited to sites of inflammation and contribute to the immune response acting as antigen presenting cells.
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Affiliation(s)
- Ricardo T. Fujiwara
- Laboratory of Cellular and Molecular Immunology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
- Department of Parasitology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Guilherme G. L. Cançado
- Laboratory of Cellular and Molecular Immunology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Paula A. Freitas
- Laboratory of Cellular and Molecular Immunology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Helton C. Santiago
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
| | - Cristiano Lara Massara
- Laboratory of Helminthology and Medical Malacology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Omar dos Santos Carvalho
- Laboratory of Helminthology and Medical Malacology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Rodrigo Corrêa-Oliveira
- Laboratory of Cellular and Molecular Immunology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Stefan M. Geiger
- Laboratory of Cellular and Molecular Immunology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Jeffrey Bethony
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
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Han S, Norimine J, Palmer GH, Mwangi W, Lahmers KK, Brown WC. Rapid deletion of antigen-specific CD4+ T cells following infection represents a strategy of immune evasion and persistence for Anaplasma marginale. THE JOURNAL OF IMMUNOLOGY 2008; 181:7759-69. [PMID: 19017965 DOI: 10.4049/jimmunol.181.11.7759] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Acquired T cell immunity is central for protection against infection. However, the immunological consequences of exposing memory T cells to high Ag loads during acute and persistent infection with systemic pathogens are poorly understood. We investigated this by using infection with Anaplasma marginale, a ruminant pathogen that replicates to levels of 10(9) bacteria per ml of blood during acute infection and maintains mean bacteremia levels of 10(6) per ml during long-term persistent infection. We established that immunization-induced Ag-specific peripheral blood CD4(+) T cell responses were rapidly and permanently lost following infection. To determine whether these T cells were anergic, sequestered in the spleen, or physically deleted from peripheral blood, CD4(+) T lymphocytes from the peripheral blood specific for the major surface protein (MSP) 1a T cell epitope were enumerated by DRB3*1101 tetramer staining and FACS analysis throughout the course of immunization and challenge. Immunization induced significant epitope-specific T lymphocyte responses that rapidly declined near peak bacteremia to background levels. Concomitantly, the mean frequency of tetramer(+)CD4(+) cells decreased rapidly from 0.025% before challenge to a preimmunization level of 0.0003% of CD4(+) T cells. Low frequencies of tetramer(+)CD4(+) T cells in spleen, liver, and inguinal lymph nodes sampled 9-12 wk postchallenge were consistent with undetectable or unsustainable Ag-specific responses and the lack of T cell sequestration. Thus, infection of cattle with A. marginale leads to the rapid loss of Ag-specific T cells and immunologic memory, which may be a strategy for this pathogen to modulate the immune response and persist.
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Affiliation(s)
- Sushan Han
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA
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32
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Semnani RT, Venugopal PG, Mahapatra L, Skinner JA, Meylan F, Chien D, Dorward DW, Chaussabel D, Siegel RM, Nutman TB. Induction of TRAIL- and TNF-alpha-dependent apoptosis in human monocyte-derived dendritic cells by microfilariae of Brugia malayi. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2008; 181:7081-9. [PMID: 18981128 PMCID: PMC3662363 DOI: 10.4049/jimmunol.181.10.7081] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dysregulation of professional APC has been postulated as a major mechanism underlying Ag-specific T cell hyporesponsiveness in patients with patent filarial infection. To address the nature of this dysregulation, dendritic cells (DC) and macrophages generated from elutriated monocytes were exposed to live microfilariae (mf), the parasite stage that circulates in blood and is responsible for most immune dysregulation in filarial infections. DC exposed to mf for 24-96 h showed a marked increase in cell death and caspase-positive cells compared with unexposed DC, whereas mf exposure did not induce apoptosis in macrophages. Interestingly, 48-h exposure of DC to mf induced mRNA expression of the proapoptotic gene TRAIL and both mRNA and protein expression of TNF-alpha. mAb to TRAIL-R2, TNF-R1, or TNF-alpha partially reversed mf-induced cell death in DC, as did knocking down the receptor for TRAIL-R2 using small interfering RNA. The mf also induced gene expression of BH3-interacting domain death agonist and protein expression of cytochrome c in DC; mf-induced cleavage of BH3-interacting domain death agonist could be shown to induce release of cytochrome c, leading to activation of caspase 9. Our data suggest that mf induce DC apoptosis in a TRAIL- and TNF-alpha-dependent fashion.
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Affiliation(s)
- Roshanak Tolouei Semnani
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20872, USA.
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Doligalska M, Donskow-Schmelter K, Rzepecka J, Drela N. Reduced apoptosis in BALB/c mice infected with Heligmosomoides polygyrus. Parasite Immunol 2007; 29:283-91. [PMID: 17518947 DOI: 10.1111/j.1365-3024.2007.00946.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We evaluated levels of apoptosis and the immune response ex vivo in BALB/c mice infected with Heligmosomoides polygyrus. Cell proliferation, apoptosis and cytokine production were measured in mesenteric lymph nodes (MLN) without exposure to H. polygyrus antigens in culture. The inhibited apoptosis and cytokine production reported might reflect a state of cell hyporesponsiveness in the prepatent phase of infection. These changes were accompanied by changes in the percentage of CD4+ cells in MLN and popliteal lymph nodes (PLN). The prolonged reduction in apoptosis coexisted with induced cell proliferation, elevated TNF-alpha, IL-12p70, IFN-gamma, IL-6, IL-10 and TGF-beta synthesis, but lowered IL-4 and IL-2 levels. In the chronic phase of infection an increasing production of IFN-gamma, monocyte chemotactic protein-1 (MCP-1), IL-10 and TGF-beta with decreasing concentrations of other cytokines resulted in restored apoptosis. The cytokine response in serum showed moderate production of TNF-alpha, temporary involvement of IL-12p70, induction of IFN-gamma and IL-10 synthesis, as well as growing IL-6 and MCP-1 production. It is suggested that a synchronized synthesis of distinct cytokines is accompanied by different levels of inhibited apoptosis during the prepatent and chronic phases of H. polygyrus infection in BALB/c mice. We suggest that immunosuppression provoked by the nematode is not the outcome of parasite-induced apoptosis, but rather results from a hyporesponsiveness experienced by cells during H. polygyrus infection.
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Affiliation(s)
- M Doligalska
- Department of Parasitology, University of Warsaw, Warsaw, Poland.
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Schaumburg F, Hippe D, Vutova P, Lüder CGK. Pro- and anti-apoptotic activities of protozoan parasites. Parasitology 2006; 132 Suppl:S69-85. [PMID: 17018167 DOI: 10.1017/s0031182006000874] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
During infection, programmed cell death, i.e. apoptosis, is an important effector mechanism of innate and adaptive host responses to parasites. In addition, it fulfils essential functions in regulating host immunity and tissue homeostasis. Not surprisingly, however, adaptation of parasitic protozoa to their hosts also involves modulation or even exploitation of cell death in order to facilitate parasite survival in a hostile environment. During recent years, considerable progress has been made in our understanding of apoptosis during parasitic infections and there is now convincing evidence that apoptosis and its modulation by protozoan parasites has a major impact on the parasite-host interaction and on the pathogenesis of disease. This review updates our current knowledge on the diverse functions apoptosis may fulfil during infections with diverse protozoan parasites including apicomplexans, kinetoplastids and amoebae. Furthermore, we also summarize common mechanistic themes of the pro- and anti-apoptotic activities of protozoan parasites. The diverse and complex effects which parasitic protozoa exert on apoptotic cell death within the host highlight fascinating interactions of parasites and their hosts. Importantly, they also stress the importance of further investigations before the modulation of host cell apoptosis can be exploited to combat parasitic infections.
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Affiliation(s)
- F Schaumburg
- Institute for Medical Microbiology, Georg-August-University, Kreuzbergring 57, 37075 Göttingen, Germany
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35
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Semnani RT, Keiser PB, Coulibaly YI, Keita F, Diallo AA, Traore D, Diallo DA, Doumbo OK, Traore SF, Kubofcik J, Klion AD, Nutman TB. Filaria-induced monocyte dysfunction and its reversal following treatment. Infect Immun 2006; 74:4409-17. [PMID: 16861626 PMCID: PMC1539612 DOI: 10.1128/iai.01106-05] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Monocyte dysfunction in filarial infection has been proposed as one mechanism underlying the diminished antigen-specific T-cell response seen in patent lymphatic filariasis. Cytokine/chemokine production and gene expression in monocytes from filaria-infected patients and uninfected healthy donors were assessed unstimulated and in response to stimulation with Staphylococcus aureus Cowan I bacteria plus gamma interferon both before and 8 months following treatment. Monocytes from filaria-infected individuals were studded with intracellular microfilarial antigens. Furthermore, monocytes from these individuals were less capable of producing interleukin-8 (IL-8), Exodus II, MIP-1alpha, MIP-1beta, and IL-1alpha and preferentially expressed genes involved in apoptosis and adhesion compared with monocytes from uninfected donors. Eight months following treatment with a single dose of ivermectin-albendazole, some of these defects were reversed, with monocyte production of IL-8, IL-1alpha, MIP-1alpha, and IL-10 being comparable to that seen in the uninfected controls. In addition, a marked increase in mRNA expression of genes associated with protein metabolism, particularly heat shock proteins, was seen compared with pretreatment expression. These data suggest that the function and gene expression of monocytes in filaria-infected patients are altered but that this dysfunction is partially reversible following antifilarial treatment.
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Affiliation(s)
- Roshanak Tolouei Semnani
- Helminth Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, 4 Center Drive, Room 4/126, National Institutes of Health, Bethesda, Maryland 20892, USA.
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36
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Clarêncio J, de Oliveira CI, Bomfim G, Pompeu MM, Teixeira MJ, Barbosa TC, Souza-Neto S, Carvalho EM, Brodskyn C, Barral A, Barral-Netto M. Characterization of the T-cell receptor Vbeta repertoire in the human immune response against Leishmania parasites. Infect Immun 2006; 74:4757-65. [PMID: 16861664 PMCID: PMC1539606 DOI: 10.1128/iai.00265-06] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Accepted: 05/16/2006] [Indexed: 12/29/2022] Open
Abstract
In order to explore a possible presence of hyperreactive T-cell clones in human cutaneous leishmaniasis (CL), we have investigated, by flow cytometry, the expression of Vbeta chains of T-cell receptors (TCRs) in the following types of cells: (i) peripheral blood mononuclear cells (PBMCs) from CL patients, which were then compared to those from normal volunteers; (ii) unstimulated and soluble Leishmania antigen-stimulated draining lymph node cells from CL patients; (iii) PBMCs from volunteers before versus after Leishmania immunization; and (iv) PBMCs from healthy volunteers that were primed in vitro with live Leishmania parasites. Our results show a modulation in the TCR Vbeta repertoire during CL and after antigen stimulation of patients' cells. Vaccination, however, leads to a broad expansion of different Vbeta TCRs. We also observed an association between TCR Vbeta12 expression, T-cell activation, and gamma interferon production upon in vitro priming with Leishmania. Collectively, these results both indicate that infection with live parasites or exposure to parasite antigen can modulate the TCR Vbeta repertoire and suggest that TCR Vbeta12 may be implicated in the response to Leishmania.
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Affiliation(s)
- Jorge Clarêncio
- Centro de Pesquisas Gonçalo Moniz, FIOCRUZ, Rua Waldemar Falcão, 121, Salvador, Bahia 40296-710, Brazil.
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37
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Turner JD, Langley RS, Johnston KL, Egerton G, Wanji S, Taylor MJ. Wolbachia Endosymbiotic Bacteria of Brugia malayi Mediate Macrophage Tolerance to TLR- and CD40-Specific Stimuli in a MyD88/TLR2-Dependent Manner. THE JOURNAL OF IMMUNOLOGY 2006; 177:1240-9. [PMID: 16818783 DOI: 10.4049/jimmunol.177.2.1240] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Lymphatic filarial nematodes are able to down-regulate parasite-specific and nonspecific responses of lymphocytes and APC. Lymphatic filariae are reliant on Wolbachia endosymbiotic bacteria for development and survival. We tested the hypothesis that repeated exposure to Wolbachia endosymbionts would drive macrophage tolerance in vitro and in vivo. We pre-exposed murine peritoneal-elicited macrophages to soluble extracts of Brugia malayi female worms (BMFE) before restimulating with BMFE or TLR agonists. BMFE tolerized macrophages (in terms of IFN-beta, IL-1beta, IL-6, IL-12p40, and TNF-alpha inflammatory cytokine production) in a dose-dependent manner toward self, LPS, MyD88-dependent TLR2 or TLR9 ligands (peptidoglycan, triacyl lipopeptide, CpG DNA) and the MyD88-independent/TRIF-dependent TLR3 ligand, polyinosinic-polycytidylic acid. This was accompanied with down-regulation in surface expression of TLR4 and up-regulation of CD14, CD40, and TLR2. BMFE tolerance extended to CD40 activation in vitro and systemic inflammation following lethal challenge in an in vivo model of endotoxin shock. The mechanism of BMFE-mediated macrophage tolerance was dependent on MyD88 and TLR2 but not TLR4. Evidence that desensitization was driven by Wolbachia-specific ligands was determined by use of extracts from Wolbachia-depleted B. malayi, aposymbiotic filarial species, and a cell line stably infected with Wolbachia pipientis. Our data promote a role for Wolbachia in contributing toward the dysregulated and tolerized immunological phenotype that accompanies the majority of human filarial infections.
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MESH Headings
- Adaptor Proteins, Signal Transducing/physiology
- Animals
- Brugia malayi/immunology
- Brugia malayi/microbiology
- CD40 Antigens/biosynthesis
- CD40 Antigens/physiology
- Cells, Cultured
- Dose-Response Relationship, Immunologic
- Down-Regulation/immunology
- Female
- Immune Tolerance
- Lipopolysaccharide Receptors/biosynthesis
- Lipopolysaccharides/administration & dosage
- Lipopolysaccharides/pharmacology
- Macrophage Activation/immunology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Macrophages, Peritoneal/microbiology
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Knockout
- Myeloid Differentiation Factor 88
- Symbiosis/immunology
- Toll-Like Receptor 2/biosynthesis
- Toll-Like Receptor 2/deficiency
- Toll-Like Receptor 2/genetics
- Toll-Like Receptor 2/physiology
- Toll-Like Receptor 4/antagonists & inhibitors
- Toll-Like Receptor 4/biosynthesis
- Transforming Growth Factor beta/biosynthesis
- Transforming Growth Factor beta1
- Up-Regulation/immunology
- Wolbachia/immunology
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Affiliation(s)
- Joseph D Turner
- Filariasis Research Laboratory, Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA Liverpool, United Kingdom
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Taylor MD, Harris A, Nair MG, Maizels RM, Allen JE. F4/80+Alternatively Activated Macrophages Control CD4+T Cell Hyporesponsiveness at Sites Peripheral to Filarial Infection. THE JOURNAL OF IMMUNOLOGY 2006; 176:6918-27. [PMID: 16709852 DOI: 10.4049/jimmunol.176.11.6918] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Both T cells and APC have been strongly implicated in the immune suppression observed during filarial nematode infections, but their relative roles are poorly understood, particularly in regard to timing and locality of action. Using Litomosoides sigmodontis infection of susceptible BALB/c mice, we have studied the progression of filarial immunosuppression leading to patent infection with blood microfilaremia. Patent infection is associated with decreased immune responsiveness in the draining thoracic lymph nodes (tLN) and intrinsically hyporesponsive CD4+ T cells at the infection site. We now show that we are able to separate, both in time and space, different suppressive mechanisms and cell populations that contribute to filarial hyporesponsiveness. L. sigmodontis infection recruited a F4/80+ population of alternatively activated macrophages that potently inhibited Ag-specific CD4+ T cell proliferative responses even in the presence of competent naive APC. T cell responsiveness was partially restored by neutralizing TGF-beta, but not by blocking IL-10 or CTLA-4 signaling. During prepatent infection, the macrophage population was restricted to the infection site. However, once infection became patent with systemic release of microfilariae, the suppressive macrophage activity extended peripherally into the tLN. In contrast, the hyporesponsive CD4+ T cell phenotype remained localized at the infection site, and the tLN CD4+ T cell population recovered full Ag responsiveness in the absence of suppressive macrophages. Filarial immunosuppression, therefore, evolves over time at sites increasingly distal to infection, and the mechanisms of filarial down-regulation are dependent on proximity to the infection site.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigen-Presenting Cells/immunology
- Antigen-Presenting Cells/parasitology
- Antigen-Presenting Cells/pathology
- Antigens, Differentiation/biosynthesis
- Antigens, Differentiation/physiology
- Antigens, Differentiation, Myelomonocytic/physiology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD4-Positive T-Lymphocytes/parasitology
- Cell Movement/immunology
- Cells, Cultured
- Female
- Filariasis/immunology
- Filariasis/parasitology
- Filariasis/pathology
- Filarioidea/growth & development
- Filarioidea/immunology
- Immune Tolerance
- Immunophenotyping
- Lymph Nodes/immunology
- Lymph Nodes/parasitology
- Lymph Nodes/pathology
- Macrophage Activation/immunology
- Mice
- Mice, Inbred BALB C
- Mice, Transgenic
- Molecular Sequence Data
- Pleural Cavity/immunology
- Pleural Cavity/parasitology
- Pleural Cavity/pathology
- T-Lymphocytes, Regulatory/cytology
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/parasitology
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Affiliation(s)
- Matthew D Taylor
- Institute of Immunology and Infection Research, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
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Dalton DK, Wittmer S. Nitric-oxide-dependent and independent mechanisms of protection from CNS inflammation during Th1-mediated autoimmunity: evidence from EAE in iNOS KO mice. J Neuroimmunol 2004; 160:110-21. [PMID: 15710464 DOI: 10.1016/j.jneuroim.2004.11.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Revised: 11/10/2004] [Accepted: 11/10/2004] [Indexed: 10/26/2022]
Abstract
Experimental autoimmune encephalomyelitis (EAE) disease was accelerated iNOS-deficient (KO) mice: coinciding with greatly increased numbers of Ag-specific Th1 cells in the periphery that appeared to rapidly shift from the spleen to the CNS during onset of disease symptoms. iNOS KO mice had significantly increased Th1 cells in the CNS versus wild-type mice. Apoptosis of CNS-infiltrating CD4(+) T cells was impaired in iNOS KO mice at peak of disease; consequently, these mice had more CNS-infiltrating CD4(+) T cells. Subsequently, iNOS KO mice up-regulated apoptosis of CNS-CD4(+) T cells. During chronic EAE, CNS macrophages were greatly decreased, suggesting elimination of CNS-infiltrating CD4(+) T cells and activated macrophages by iNOS-independent mechanisms. INOS is not only required for apoptosis of CNS-CD4(+) T cells but also prevents overexpansion of autoreactive Th1 cells in the periphery and the CNS.
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MESH Headings
- Adjuvants, Immunologic/physiology
- Animals
- Apoptosis/genetics
- Apoptosis/immunology
- CD4 Lymphocyte Count
- CD4-Positive T-Lymphocytes/enzymology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/pathology
- Cell Movement/genetics
- Cell Movement/immunology
- Cells, Cultured
- Central Nervous System/enzymology
- Central Nervous System/immunology
- Central Nervous System/pathology
- Chronic Disease
- Disease Progression
- Encephalomyelitis, Autoimmune, Experimental/enzymology
- Encephalomyelitis, Autoimmune, Experimental/genetics
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Encephalomyelitis, Autoimmune, Experimental/prevention & control
- Epitopes, T-Lymphocyte/immunology
- Interferon-gamma/deficiency
- Interferon-gamma/genetics
- Interferon-gamma/physiology
- Macrophage Activation/genetics
- Macrophage Activation/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Myelin Proteins
- Myelin-Associated Glycoprotein/immunology
- Myelin-Oligodendrocyte Glycoprotein
- Nitric Oxide/physiology
- Nitric Oxide Synthase/deficiency
- Nitric Oxide Synthase/genetics
- Nitric Oxide Synthase/physiology
- Nitric Oxide Synthase Type II
- Severity of Illness Index
- Th1 Cells/enzymology
- Th1 Cells/immunology
- Th1 Cells/pathology
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Affiliation(s)
- Dyana K Dalton
- Trudeau Institute Inc., 154 Algonquin Ave, Saranac Lake, NY 12983, USA.
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Semnani RT, Nutman TB. Toward an understanding of the interaction between filarial parasites and host antigen-presenting cells. Immunol Rev 2004; 201:127-38. [PMID: 15361237 DOI: 10.1111/j.0105-2896.2004.00196.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Lymphatic filarial infection, from an immunologic point of view, is one of the most complex parasite infections. Not only are there different clinical manifestations that reflect differing immune responses, but the parasite's multiple stages, each with distinct anatomic tropism, add a compartmental layer of complexity to an already complicated process. Moreover, these parasites have finely tuned immune evasion strategies that enable escape from the innate immune system. As different stages of the parasite interact with different types of antigen-presenting cells that, in turn, may play a significant role in shaping the subsequent adaptive immune response, the focus of this review is to provide insight into the interaction between filarial parasites and antigen-presenting cells with an eye toward understanding how they influence parasite antigen-driven T-cell responses.
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Affiliation(s)
- Roshanak Tolouei Semnani
- Helminth Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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Affiliation(s)
- Eric R James
- Department of Ophthalmology, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29425, USA.
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O'Connor RA, Jenson JS, Osborne J, Devaney E. An enduring association? Microfilariae and immunosuppression [correction of immunosupression] in lymphatic filariasis. Trends Parasitol 2004; 19:565-70. [PMID: 14642766 DOI: 10.1016/j.pt.2003.09.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Rutitzky LI, Mirkin GA, Stadecker MJ. Apoptosis by neglect of CD4+ Th cells in granulomas: a novel effector mechanism involved in the control of egg-induced immunopathology in murine schistosomiasis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:1859-67. [PMID: 12902487 DOI: 10.4049/jimmunol.171.4.1859] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In infection with Schistosoma mansoni, parasite eggs precipitate an intrahepatic granulomatous and fibrosing inflammation that is mediated by CD4(+) Th cells. Compared with CBA mice, C57BL/6 mice develop smaller granulomas composed of cells that exhibit reduced proliferative responses to schistosome egg Ags. In the present study, we investigated CD4(+) T cell apoptosis as a possible mechanism that could account for this subdued response. We found throughout the course of several infection weeks a markedly higher proportion of apoptotic CD4(+) T cells in granulomas from C57BL/6 mice than in those from CBA mice ex vivo; the apoptosis further increased upon cell cultivation in vitro. Activation-induced cell death or CD8(+) T cells failed to account for the enhanced apoptosis as infected Fas-, Fas ligand,- and CD8-deficient mice exhibited similar apoptosis to that seen in wild-type counterparts. However, a strikingly lower IL-2 production by schistosome egg Ag-stimulated C57BL/6 granuloma and mesenteric lymph node cells suggested the possibility of apoptosis due to growth factor deprivation. Indeed, the CD4(+) T cell apoptosis was significantly reversed by addition of rIL-2 in vitro, or by injection of rIL-2 in vivo, which also resulted in significant exacerbation of granulomatous inflammation. These findings indicate that apoptosis by neglect can represent a significant means of controlling CD4(+) T cells that mediate the immunopathology in schistosomiasis.
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Affiliation(s)
- Laura I Rutitzky
- Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, USA
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Semnani RT, Liu AY, Sabzevari H, Kubofcik J, Zhou J, Gilden JK, Nutman TB. Brugia malayi microfilariae induce cell death in human dendritic cells, inhibit their ability to make IL-12 and IL-10, and reduce their capacity to activate CD4+ T cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:1950-60. [PMID: 12902498 DOI: 10.4049/jimmunol.171.4.1950] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Parasite Ag-specific T cell unresponsiveness and diminished IFN-gamma production are immunologic hallmarks of patent infection with lymph-dwelling filarial nematodes. Although this diminished responsiveness is directed primarily against the intravascular microfilarial (MF) parasite stage and mediated in part by reduced APC function, the mechanisms involved are not fully understood. In this report, we demonstrate that human dendritic cells (DC) exposed to live MF up-regulate both the cell surface and gene expression of CD54 (ICAM-1). Moreover, live MF result in a 3-fold increase in DC death compared with MF-unexposed DC, primarily due to apoptosis. Notably, microarray and real-time RT-PCR data indicate that live MF concurrently up-regulate mRNA expression of proinflammatory molecules such as IL-8, RANTES, IL-1alpha, TNF-alpha, and IL-beta in DC, the presence of which is also detected at the protein level, while inhibiting the production of IL-12 (p40 and p70) and IL-10. Soluble excretory-secretory products from live MF diminished IL-12 and IL-10 production and induced DC death, although to a lesser degree. Moreover, exposure of DC to live MF resulted in a decrease in the ability of DC to promote CD4(+) T cell production of IFN-gamma and IL-5. Our findings clearly suggest that the interaction between live MF and DC is complex but contributes to the hyporesponsiveness and parasite persistence associated with the MF(+) state in the infected human. These data further suggest that MF induce an orchestrated response in APC that leads to a diminished capacity to function appropriately, which in turn has significant consequences for CD4(+) T cells.
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Affiliation(s)
- Roshanak Tolouei Semnani
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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Jasmer DP, Goverse A, Smant G. Parasitic nematode interactions with mammals and plants. ANNUAL REVIEW OF PHYTOPATHOLOGY 2003; 41:245-70. [PMID: 14527330 DOI: 10.1146/annurev.phyto.41.052102.104023] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Parasitic nematodes that infect humans, animals, and plants cause serious diseases that are deleterious to human health and agricultural productivity. Chemical and biological control methods have reduced the impact of these parasites. However, surviving environmental stages lead to persistent reinfection of host species. In addition, development of resistance to nematicides and anthelmintics by these parasites and reduced availability of some nematicides, for environmental protection, pose significant obstacles for current and future prospects of effective parasite control. Due to marked differences in host species, research on animal and plant parasitic nematodes often proceeds independently. Despite the differences between animals and plants, basic cellular properties are shared among these host organisms. Some common properties may be important for mechanisms [homologous or convergent (homoplastic)] by which nematodes successfully infect these diverse hosts or by which animal and plant hosts resist infections by these pathogens. Here we compare host/parasite interactions between plant parasitic nematodes (PPN) and animal parasitic nematodes, with an emphasis on mammalian hosts (MPN). Similarities and differences are considered in the context of progress on molecular dissection of these interactions. A comprehensive coverage is not possible in the space allotted. Instead, an illustrative approach is used to establish examples that, it is hoped, exemplify the value of the comparative approach.
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Affiliation(s)
- Douglas P Jasmer
- Department of Veterinary Microbiology, Washington State University, Pullman, Washington, 99164-7040, USA.
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O'Connor RA, Devaney E. Nitric oxide limits the expansion of antigen-specific T cells in mice infected with the microfilariae of Brugia pahangi. Infect Immun 2002; 70:5997-6004. [PMID: 12379675 PMCID: PMC130375 DOI: 10.1128/iai.70.11.5997-6004.2002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2002] [Revised: 06/29/2002] [Accepted: 07/27/2002] [Indexed: 11/20/2022] Open
Abstract
Infection of BALB/c mice with the microfilariae (Mf) of the filarial nematode Brugia pahangi results in an antigen-specific proliferative defect that is induced by high levels of NO. Using carboxyfluorescein diacetate succinimydl ester and cell surface labeling, it was possible to identify a population of antigen-specific T cells from Mf-infected BALB/c mice that expressed particularly high levels of CD4 (CD4(hi)). These cells proliferated in culture only when inducible NO synthase was inhibited and accounted for almost all of the antigen-specific proliferative response under those conditions. CD4(hi) cells also expressed high levels of CD44, consistent with their status as activated T cells. A similar population of CD4(hi) cells was observed in cultures from Mf-infected gamma interferon receptor knockout (IFN-gammaR(-/-)) mice. Terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling staining revealed that the CD4(+) T cells from Mf-infected wild-type mice were preferentially susceptible to apoptosis compared to CD4(+) T cells from IFN-gammaR(-/-) mice. These studies suggest that the expansion of antigen-specific T cells in Mf-infected mice is limited by NO.
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Affiliation(s)
- Richard A O'Connor
- Department of Veterinary Parasitology, University of Glasgow, Glasgow G61 1QH, Scotland
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