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Miller Jenkins LM, Ott DE, Hayashi R, Coren LV, Wang D, Xu Q, Schito ML, Inman JK, Appella DH, Appella E. Small-molecule inactivation of HIV-1 NCp7 by repetitive intracellular acyl transfer. Nat Chem Biol 2010; 6:887-9. [PMID: 20953192 DOI: 10.1038/nchembio.456] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 09/15/2010] [Indexed: 11/09/2022]
Abstract
The zinc fingers of the HIV-1 nucleocapsid protein, NCp7, are prime targets for antiretroviral therapeutics. Here we show that S-acyl-2-mercaptobenzamide thioester (SAMT) chemotypes inhibit HIV by modifying the NCp7 region of Gag in infected cells, thereby blocking Gag processing and reducing infectivity. The thiol produced by SAMT reaction with NCp7 is acetylated by cellular enzymes to regenerate active SAMTs via a recycling mechanism unique among small-molecule inhibitors of HIV.
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Affiliation(s)
- Lisa M Miller Jenkins
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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Mehra V, Musib R, Schito ML. Towards developing standardized protocols for evaluation of cellular mucosal immune responses - Recommendations from a DAIDS/NIH workshop, June 15-16, 2009. Vaccine 2010; 28:4689-94. [PMID: 20470800 DOI: 10.1016/j.vaccine.2010.04.092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 04/15/2010] [Accepted: 04/27/2010] [Indexed: 10/19/2022]
Abstract
Although 80% of HIV infections occur through mucosal routes and vaccine strategies need to be designed for inducing protective immune responses at the site of the viral entry, it has proven to be very challenging to measure these responses. A 2-day workshop was convened by Division of AIDS, National Institutes of Health on June 15-16, 2009 to address the challenges encountered in the evaluation of mucosal T cell immune responses. The goal of the workshop was to obtain recommendations/consensus for developing standardized protocols for the assessment of mucosal immunity. This report summarizes the areas of consensus and recommendations that should assist in developing standardized methodologies for the evaluation of mucosal immune responses.
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Affiliation(s)
- V Mehra
- Preclinical Research and Development Branch, Vaccine Research Program, Division of AIDS, NIAID, NIH, HHS, USA
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3
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Abstract
The introduction of serological point-of-care assays 10 years ago dramatically changed the way that human immunodeficiency virus (HIV) infection was identified and diagnosed. Testing at the point of care has lead to a dramatic increase in the number of individuals who are screened and, most importantly, receive their HIV test result. As the AIDS epidemic continues to mature and scientific advances in prevention and treatment are evaluated and implemented, there is a need to identify acute (viremic preseroconversion) infections and to discriminate "window phase" infections from those that are serologically positive, especially in resource-limited settings, where the majority of vulnerable populations reside and where the incidence of HIV infection is highest. Rapid testing methods are now at a crossroads. There is opportunity to implement and evaluate the incremental diagnostic usefulness of new test modalities that are based on sophisticated molecular diagnostic technologies and that can be performed in settings where laboratory infrastructure is minimal. The way forward requires sound scientific judgment and an ability to further develop and implement these tests despite a variety of technical, social, and operational hurdles, to declare success.
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Affiliation(s)
- Marco L Schito
- Henry Jackson Foundation for the Advancement of Military Medicine, Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20817, USA.
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Turpin JA, Schito ML, Jenkins LMM, Inman JK, Appella E. Topical microbicides: a promising approach for controlling the AIDS pandemic via retroviral zinc finger inhibitors. Adv Pharmacol 2008; 56:229-56. [PMID: 18086414 DOI: 10.1016/s1054-3589(07)56008-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Affiliation(s)
- Jim A Turpin
- Preventions Sciences Program, Division of AIDS, NIAID, National Institutes of Health, Bethesda, Maryland 20892, USA
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Schito ML, Soloff AC, Slovitz D, Trichel A, Inman JK, Appella E, Turpin JA, Barratt-Boyes SM. Preclinical Evaluation of a Zinc Finger Inhibitor Targeting Lentivirus Nucleocapsid Protein in SIV-Infected Monkeys. Curr HIV Res 2006; 4:379-86. [PMID: 16842089 DOI: 10.2174/157016206777709492] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is a continued need to develop inexpensive and effective drugs specific for novel targets of human immunodeficiency virus type 1 (HIV-1). The HIV-1 nucleocapsid p7 (NCp7) protein plays a critical role in early and late stages of the virus life cycle and possesses two highly conserved retroviral zinc fingers that are essential for its function. We have previously shown that zinc finger inhibitors (ZFI) based on the S-acyl 2-mercaptobenzamide thioester (SAMT) chemotype specifically target HIV NCp7 and are effective at reducing levels of infectious virus in an HIV-1-transgenic mouse model. Here, we did an initial proof-of-concept study to test the potential of a lead SAMT compound to reduce virus infectivity in the simian immunodeficiency virus (SIV) nonhuman primate model. SAMT-19 had potent antiviral and virucidal effects against the primary pathogenic isolate SIV/DeltaB670 and was non-cytotoxic in vitro. Cynomolgus macaques were infected intrarectally with SIV/DeltaB670 and treated with a low dose of SAMT-19 by continuous infusion from day 8 to day 28 post infection. Monkeys in the treatment group had significantly lower levels of infectious virus in peripheral blood mononuclear cells during the course of therapy as compared to monkeys in the control group, although therapy had no demonstrable effect on virus load. SAMT-19 therapy did not alter liver, kidney or immunologic function and was well tolerated by all treated monkeys. These data demonstrate that SAMT-19 is safe and virucidal in the nonhuman primate model. Further studies directed at optimizing SAMT bioavailability and pharmacokinetics likely will result in enhanced therapeutic efficacy of this promising HIV therapeutic.
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Affiliation(s)
- Marco L Schito
- Laboratory of Cell Biology, National Cancer Institute, National Institute of Health, Bethesda, Maryland 20892, USA.
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Schito ML, Demidov ON, Saito S, Ashwell JD, Appella E. Wip1 Phosphatase-Deficient Mice Exhibit Defective T Cell Maturation Due To Sustained p53 Activation. J Immunol 2006; 176:4818-25. [PMID: 16585576 DOI: 10.4049/jimmunol.176.8.4818] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The PP2C phosphatase Wip1 dephosphorylates p38 and blocks UV-induced p53 activation in cultured human cells. Although the level of TCR-induced p38 MAPK activity is initially comparable between Wip1-/- and wild-type thymocytes, phosphatase-deficient cells failed to down-regulate p38 MAPK activity after 6 h. Analysis of young Wip1-deficient mice showed that they had fewer splenic T cells. Their thymi were smaller, contained significantly fewer cells, and failed to undergo age-dependent involution compared with wild-type animals. Analysis of thymocyte subset numbers by flow cytometry suggested that cell numbers starting at the double-negative (DN)4 stage are significantly reduced in Wip1-deficient mice, and p53 activity is elevated in cell-sorted DN4 and double-positive subpopulations. Although apoptosis and proliferation was normal in Wip1-/- DN4 cells, they appeared to be in cell cycle arrest. In contrast, a significantly higher percentage of apoptotic cells were found in the double-positive population, and down-regulation of thymocyte p38 MAPK activation by anti-CD3 was delayed. To examine the role of p38 MAPK in early thymic subpopulations, fetal thymic organ cultures cultured in the presence/absence of a p38 MAPK inhibitor did not correct the thymic phenotype. In contrast, the abnormal thymic phenotype of Wip1-deficient mice was reversed in the absence of p53. These data suggest that Wip1 down-regulates p53 activation in the thymus and is required for normal alphabeta T cell development.
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Affiliation(s)
- Marco L Schito
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Báfica A, Scanga CA, Schito ML, Hieny S, Sher A. Cutting edge: in vivo induction of integrated HIV-1 expression by mycobacteria is critically dependent on Toll-like receptor 2. J Immunol 2003; 171:1123-7. [PMID: 12874196 DOI: 10.4049/jimmunol.171.3.1123] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Mycobacterial infection has been implicated as a possible factor in AIDS progression in populations where HIV-1 and Mycobacterium tuberculosis are coendemic. In support of this concept, we have previously shown that HIV-1-transgenic (Tg) mice infected with mycobacteria display enhanced viral gene and protein expression. In this study, we demonstrate that the induction of HIV-1 observed in this model is dependent on Toll-like receptor 2 (TLR2), a pattern recognition receptor known to be involved in mycobacteria-host interaction. Spleen cells from HIV-1-Tg mice deficient in TLR2 (Tg/TLR2(-/-)) were found to be completely defective in p24 production induced in response to live M. tuberculosis or Mycobacterium avium as well as certain mycobacterial products. Importantly, following in vivo mycobacterial infection, Tg/TLR2(-/-) mice failed to display the enhanced HIV-1 gag/env mRNA and p24 protein synthesis exhibited by wild-type Tg animals. Together, these results argue that TLR2 plays a crucial role in the activation of HIV-1 expression by mycobacterial coinfections.
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Affiliation(s)
- André Báfica
- Immunobiology Section, National Institute of Allergy and Infectious Diseases and. Chemical Immunology Section, Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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8
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Equils O, Schito ML, Karahashi H, Madak Z, Yarali A, Michelsen KS, Sher A, Arditi M. Toll-like receptor 2 (TLR2) and TLR9 signaling results in HIV-long terminal repeat trans-activation and HIV replication in HIV-1 transgenic mouse spleen cells: implications of simultaneous activation of TLRs on HIV replication. J Immunol 2003; 170:5159-64. [PMID: 12734363 DOI: 10.4049/jimmunol.170.10.5159] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Opportunistic infections are common in HIV-infected patients; they activate HIV replication and contribute to disease progression. In the present study we examined the role of Toll-like receptor 2 (TLR2) and TLR9 in HIV-long terminal repeat (HIV-LTR) trans-activation and assessed whether TLR4 synergized with TLR2 or TLR9 to induce HIV replication. Soluble Mycobacterium tuberculosis factor (STF) and phenol-soluble modulin from Staphylococcus epidermidis induced HIV-LTR trans-activation in human microvessel endothelial cells cotransfected with TLR2 cDNA. Stimulation of ex vivo spleen cells from HIV-1 transgenic mice with TLR4, TLR2, and TLR9 ligands (LPS, STF, and CpG DNA, respectively) induced p24 Ag production in a dose-dependent manner. Costimulation of HIV-1 transgenic mice spleen cells with LPS and STF or CpG DNA induced TNF-alpha and IFN-gamma production in a synergistic manner and p24 production in an additive fashion. In the THP-1 human monocytic cell line stably expressing the HIV-LTR-luciferase construct, LPS and STF also induced HIV-LTR trans-activation in an additive manner. This is the first time that TLR2 and TLR9 and costimulation of TLRs have been shown to induce HIV replication. Together these results underscore the importance of TLRs in bacterial Ag- and CpG DNA-induced HIV-LTR trans-activation and HIV replication. These observations may be important in understanding the role of the innate immune system and the molecular mechanisms involved in the increased HIV replication and HIV disease progression associated with multiple opportunistic infections.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adjuvants, Immunologic/metabolism
- Adjuvants, Immunologic/physiology
- Animals
- Antigens, Differentiation/pharmacology
- Cell Line, Transformed
- Cells, Cultured
- Cytokines/biosynthesis
- DNA-Binding Proteins/metabolism
- DNA-Binding Proteins/physiology
- HIV Long Terminal Repeat/genetics
- HIV Long Terminal Repeat/immunology
- HIV-1/genetics
- HIV-1/immunology
- HIV-1/physiology
- Humans
- Ligands
- Lipopolysaccharides/pharmacology
- Membrane Glycoproteins/metabolism
- Membrane Glycoproteins/physiology
- Mice
- Mice, Transgenic
- Mycobacterium tuberculosis/immunology
- Myeloid Differentiation Factor 88
- Receptors, Cell Surface/metabolism
- Receptors, Cell Surface/physiology
- Receptors, Immunologic
- Signal Transduction/genetics
- Signal Transduction/immunology
- Spleen/cytology
- Spleen/immunology
- Spleen/metabolism
- Spleen/virology
- Th1 Cells/immunology
- Th1 Cells/metabolism
- Toll-Like Receptor 2
- Toll-Like Receptor 4
- Toll-Like Receptor 9
- Toll-Like Receptors
- Transcriptional Activation/immunology
- Tumor Cells, Cultured
- Up-Regulation/genetics
- Up-Regulation/immunology
- Virus Replication/genetics
- Virus Replication/immunology
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Affiliation(s)
- Ozlem Equils
- Division of Pediatric Infectious Diseases, Steven Spielberg Pediatric Research Center, Burns and Allen Research Institute, Cedars-Sinai Medical Center, University of California School of Medicine, Los Angeles, CA 90048, USA.
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Schito ML, Goel A, Song Y, Inman JK, Fattah RJ, Rice WG, Turpin JA, Sher A, Appella E. In vivo antiviral activity of novel human immunodeficiency virus type 1 nucleocapsid p7 zinc finger inhibitors in a transgenic murine model. AIDS Res Hum Retroviruses 2003; 19:91-101. [PMID: 12639244 DOI: 10.1089/088922203762688595] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Control of human immunodeficiency virus through the use of inexpensive chemotherapeutics, with minimal side effects and decreased potential for engendering resistant virus, is a long-term therapeutic goal. In principle, this goal can be accomplished if viral replication in reservoirs of chronically and latently infected cells is addressed. As a first step, we have developed novel antiviral compounds based on a 2-mercaptobenzamide thioester chemotype, including the pyridinioalkanoyl thioesters, which specifically target the zinc fingers of the human immunodeficiency virus nucleocapsid protein (NCp7). Using these compounds in a murine transgenic model, in which infectious human immunodeficiency virus is induced from an integrated provirus, we show inhibition of transgenic spleen cell p24 expression with potencies comparable to acute infection assays using human peripheral blood lymphocytes. More importantly, transgenic mice treated in vivo with two 2-mercaptobenzamide thioesters expressed significantly lower plasma p24, and splenocytes from these animals produced fewer infectious virions. Thus, these thioesters may provide an effective means for inhibiting the expression of human immunodeficiency virus from integrated viral reservoirs.
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Affiliation(s)
- Marco L Schito
- Chemical Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA.
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10
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Schito ML, Kennedy PE, Kowal RP, Berger EA, Sher A. A human immunodeficiency virus-transgenic mouse model for assessing interventions that block microbial-induced proviral expression. J Infect Dis 2001; 183:1592-600. [PMID: 11343207 DOI: 10.1086/320716] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2001] [Revised: 03/01/2001] [Indexed: 11/03/2022] Open
Abstract
A human immunodeficiency virus (HIV) type 1-transgenic mouse line (166) that previously showed up-regulated expression of viral proteins and infectious particles after infection with pathogenic agents was tested as a model for screening the in vitro and in vivo efficacy of inhibitors of HIV-1 immune activation. Two types of interventions were assessed: use of either the immunosuppressive drug prednisolone or an HIV-1 envelope-targeted toxin (sCD4-PE40). Both agents inhibited lipopolysaccharide-induced p24 expression by splenocytes in vitro and, when administered to transgenic mice, suppressed the induction of plasma p24, as well as the ex vivo production of p24 and infectious virus stimulated by in vivo infection with Mycobacterium avium. Moreover, HIV-1 mRNA levels in the spleen were greatly reduced in mice treated with either agent. Because HIV-1 expression cannot be induced in T lymphocytes from line 166 mice, this model may be of particular advantage for testing interventions that target virus production by non-T cell virus reservoirs.
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Affiliation(s)
- M L Schito
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0425, USA.
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11
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Barta JR, Tennyson SA, Schito ML, Danforth HD, Martin DS. Partial characterization of a non-proteinaceous, low molecular weight antigen of Eimeria tenella. Parasitol Res 2000; 86:461-6. [PMID: 10894471 DOI: 10.1007/s004360050694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
A low molecular weight (LMW) antigen of Eimeria tenella, initially identified using a murine monoclonal antibody (mAb C(3)4F(1)) raised against E. tenella sporozoites, was partially characterized using enzymatic degradation. solvent extraction, and immunization into various inbred lines of mice. The LMW antigen could be isolated using Folch extraction (methanol/chloroform/ water) and the epitope recognized by mAb C(3)4F(1) was resistant to degradation by alpha-amylase, pronase, and proteinase K, but was sensitive to sodium m-periodate treatment or digestion using mixed glycosidases (from Turbo cornutus). These observations suggest that the antigenic epitope recognized by mAb C(3)4F(1) is carbohydrate-dependent and, based on our ability to isolate the LMW antigen by Folch extraction, the epitope probably resides on a polar glycolipid. The inability of sporozoite-immunized nude mice to elicit a serum antibody response to this molecule indicates that it acts as a T-dependent antigen. Furthermore, sporozoite-immunized male CBA/N mice (with an X-linked immunodeficiency) also failed to elicit a serum antibody response to this molecule, which is consistent with a carbohydrate antigenic epitope. We propose that this antigenic molecule be designated ET-GL1 to reflect its origin and probable structure (E. tenella glycolipid 1).
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Affiliation(s)
- J R Barta
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Canada.
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12
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Schito ML, Chobotar B, Barta JR. Major histocompatibility complex class I- and II-deficient knock-out mice are resistant to primary but susceptible to secondary Eimeria papillata infections. Parasitol Res 1998; 84:394-8. [PMID: 9610637 DOI: 10.1007/s004360050416] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Two distinct mechanisms seem to function in reducing oocyst output during Eimeria papillata infections in mice. For naive mice, immunity was afforded by a T-cell-independent gamma-interferon (IFN-gamma) response mediated by natural killer (NK) cells. On reinfection, resistance was associated with T-cells and, to a lesser extent, perforin. To determine if antigen presentation with major histocompatibility complex (MHC) molecules was required to control oocyst production by NK cells during primary infection or by T-cells during secondary infection, mutant mice that lacked H2-IAbeta(b) (Abeta(b)-/-) or beta2-microglobulin (beta2m-/-) were used. Since MHC molecules are required for the maturation of alphabeta T-cells, Abeta(b)-/- and beta2m-/- mutant mice are also deficient in functional alphabeta+CD4+ or alphabeta+CD8+ T-cells, respectively. As compared with wild-type control mice, oocyst output by mutant mice was not significantly affected during primary infection, suggesting that the ability of NK cells to control parasite replication is not dependent on the expression of MHC molecules. On reinfection, differences were observed for mutant mice as compared with controls. Abeta(b)-/- mice were found to be more susceptible than beta2m-/- mice, suggesting that the alphabeta+CD4+ T-cell subset plays a greater role in resistance to reinfection than does the alphabeta+CD8+ T-cell subset. The mechanism of resistance depends on the immune status of the host and requires the coordinated interaction of both alphabeta+ T-cell subsets for optimal parasite control during subsequent infections.
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Affiliation(s)
- M L Schito
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Canada
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13
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Schito ML, Chobotar B, Barta JR. Cellular dynamics and cytokine responses in BALB/c mice infected with Eimeria papillata during primary and secondary infections. J Parasitol 1998; 84:328-37. [PMID: 9576507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BALB/c mice were infected with the intestinal intracellular parasite Eimeria papillata to characterize lymphocyte responses and cytokine profiles throughout primary and secondary infections. Lymphocytes from the mesenteric lymph node (MLN) and the gastrointestinal tract (GIT) of infected mice were phenotypically analyzed using flow cytometry and immunofluorescence microscopy, respectively. Lymphocytes isolated from the MLN during primary infections of BALB/c mice with E. papillata do not proliferate, compared to day 0 uninfected controls, when stimulated in vitro with conconavalin A and express TH2-type cytokines (interleukin [IL]-4 and IL-10) on day 3 PI followed by the release of TH1-type cytokines (IL-2 and interferon-gamma) during patency. In the small intestine, significantly more T cells and their subsets were observed during primary infection. During secondary infections, IL-2 was the only 1 of the 4 cytokines that was expressed earlier and at higher levels in the MLN when compared to primary infections. In the small intestine, significantly more alphabeta+ and CD8+ T lymphocytes were observed in mice during secondary infection. Oocyst antigens did not induce cellular proliferation at any time point during primary or secondary infections. We conclude that primary oral infection of BALB/c mice with E. papillata is associated with localized immunosuppression that may be mediated, in part, by early TH2-type cytokines. Immunity to secondary infection may be mediated by intestinal alphabeta+ CD8+ T lymphocytes through an IL-2-dependent mechanism.
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Affiliation(s)
- M L Schito
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Canada
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14
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Schito ML, Chobotar B, Barta JR. Cellular Dynamics and Cytokine Responses in BALB/c Mice Infected with Eimeria papillata during Primary and Secondary Infections. J Parasitol 1998. [DOI: 10.2307/3284491] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Barta JR, Coles BA, Schito ML, Fernando MA, Martin A, Danforth HD. Analysis of infraspecific variation among five strains of Eimeria maxima from North America. Int J Parasitol 1998; 28:485-92. [PMID: 9559366 DOI: 10.1016/s0020-7519(97)00211-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Two laboratory strains from the eastern shore of Maryland 15 years ago and from an Ontario broiler house 23 years ago and three recent field strains of Eimeria maxima (isolated in Maryland, North Carolina and Florida) were examined for phenotypic and genotypic variation using protein profiles, random amplified polymorphic DNA-PCR analysis and DNA sequences obtained from the internal transcribed spacer regions of the rRNA genes. Staining profiles obtained by one-dimensional SDS-PAGE of sporozoite proteins were identical in all five strains. Using random amplified polymorphic DNA-PCR analysis with high %G-C content decamers as primers, we were able to confirm that the five strains are all E. maxima, but were unable to discern any relationships among them because of the limited number of shared polymorphisms identified. In contrast, cloning and sequencing of the internal transcribed spacer-1, 5.8S rDNA and internal transcribed spacer-2 regions of the rRNA genes provided sufficient sequence information to infer phylogenetic relationships among the strains. Almost all of the infraspecific variation was located in the internal transcribed spacer regions. Only two base changes were identified within the 5.8S rRNA gene. Evolutionary relationships among the strains inferred using parsimony analysis of the aligned internal transcribed spacer sequences were well supported, but the hypothesised relationships did not correlate well with the demonstrated immunological cross-reactivities of these strains.
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Affiliation(s)
- J R Barta
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Ont., Canada.
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Abstract
Severe combined immunodeficient (SCID)-beige mice inoculated with the intracellular parasite Eimeria papillata produced significantly more oocysts during primary infections than inoculated immunodeficient SCID mice. Therefore, the addition of the beige mutation, which detrimentally affects neutrophil and natural killer (NK) cell functions, enhanced the parasites' ability to reproduce within the small intestine. To identify which of these two cell types is responsible for a protective immune response during primary infection, the following groups of mice were inoculated: (i) SCID mice depleted of neutrophils with antigranulocyte monoclonal antibody (RB6-8C5), (ii) C57BL/6 mice depleted of NK cells with the anti-NK-1.1 monoclonal antibody (PK136), and (iii) transgenic Tg epsilon26++ mice (T and NK cell deficient). To identify the mechanisms of immunity during primary and secondary infections, gamma interferon (IFN-gamma) knockout and perforin knockout mice were inoculated. Oocyst output was found to be significantly higher during primary infection for mice depleted of NK cells by administration of anti-NK-1.1 antibodies, for Tg epsilon26++ mice, and for IFN-gamma knockout mice. During secondary infections, only perforin knockout mice produced significantly more oocysts compared to control mice. Our observations suggest that NK cells inhibit E. papillata oocyst output during primary infection by the production of IFN-gamma and that this inhibition is independent of perforin. Immunity to reinfection does not require IFN-gamma but appears to be mediated, at least in part, by a perforin-dependent mechanism.
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Affiliation(s)
- M L Schito
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Canada
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17
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Schito ML, Barta JR, Chobotar B. Comparison of four murine Eimeria species in immunocompetent and immunodeficient mice. J Parasitol 1996; 82:255-62. [PMID: 8604093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Factors associated with immune-mediated protection against coccidial parasites were examined in a series of experiments utilizing immunocompromised scid/scid(SCID) and scid/scid.beige/beige(SCID/Bg) mice, as well as immunocompetent BALB/c mice. Number of oocysts produced per g feces each day and prepatent and patent periods were assessed for 4 eimerian parasites (Eimeria papillata, Eimeria vermiformis, Eimeria falciformis, and Eimeria ferrisi) using the 3 murine strains. The number of infections required to elicit a protective immune response was also determined for each coccidial species in BALB/c mice. We report the first description of patent infections in inbred immunocompetent and immunodeficient mice infected with E. papillata. Results indicate that during primary infections, parasite replication is under partial immunological control for all Eimeria species. However, the control is mechanistically different for E. papillata because the adaptive immune response does not contribute to the control of primary infections. Both coccidial species infecting intestinal villar epithelial cells (E. papillata and E. ferrisi) were affected by the beige mutation using parasite output as an indicator, whereas E. falciformis, which infects intestinal crypt cells, is not. BALB/c mice were more resistant to challenge infections with upper intestinal parasites (E. papillata and E. vermiformis) in comparison to challenge infections with lower intestinal and cecal parasites (E. falciformis and E. ferrisi).
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Affiliation(s)
- M L Schito
- Department of Pathobiology, University of Guelph, Ontario, Canada
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Schito ML, Barta JR, Chobotar B. Comparison of Four Murine Eimeria Species in Immunocompetent and Immunodeficient Mice. J Parasitol 1996. [DOI: 10.2307/3284157] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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