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Fontana MF, Ollmann Saphire E, Pepper M. Plasmodium infection disrupts the T follicular helper cell response to heterologous immunization. eLife 2023; 12:83330. [PMID: 36715223 PMCID: PMC9886276 DOI: 10.7554/elife.83330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 01/12/2023] [Indexed: 01/31/2023] Open
Abstract
Naturally acquired immunity to malaria develops only after many years and repeated exposures, raising the question of whether Plasmodium parasites, the etiological agents of malaria, suppress the ability of dendritic cells (DCs) to activate optimal T cell responses. We demonstrated recently that B cells, rather than DCs, are the principal activators of CD4+ T cells in murine malaria. In the present study, we further investigated factors that might prevent DCs from priming Plasmodium-specific T helper cell responses. We found that DCs were significantly less efficient at taking up infected red blood cells (iRBCs) compared to soluble antigen, whereas B cells more readily bound iRBCs. To assess whether DCs retained the capacity to present soluble antigen during malaria, we measured responses to a heterologous protein immunization administered to naïve mice or mice infected with P. chabaudi. Antigen uptake, DC activation, and expansion of immunogen-specific T cells were intact in infected mice, indicating DCs remained functional. However, polarization of the immunogen-specific response was dramatically altered, with a near-complete loss of germinal center T follicular helper cells specific for the immunogen, accompanied by significant reductions in antigen-specific B cells and antibody. Our results indicate that DCs remain competent to activate T cells during Plasmodium infection, but that T cell polarization and humoral responses are severely disrupted. This study provides mechanistic insight into the development of both Plasmodium-specific and heterologous adaptive responses in hosts with malaria.
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Affiliation(s)
- Mary F Fontana
- Department of Immunology, University of Washington School of MedicineSeattleUnited States
| | - Erica Ollmann Saphire
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for ImmunologyLa JollaUnited States
| | - Marion Pepper
- Department of Immunology, University of Washington School of MedicineSeattleUnited States
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Tong ZZ, Fang ZM, Zhang Q, Zhan Y, Zhang Y, Jiang WF, Hou X, Li YL, Wang T. Plasmodium yoelii infection inhibits murine leukaemia WEHI-3 cell proliferation in vivo by promoting immune responses. Infect Dis Poverty 2018; 7:48. [PMID: 29764519 PMCID: PMC5954458 DOI: 10.1186/s40249-018-0433-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 04/25/2018] [Indexed: 11/10/2022] Open
Abstract
Background Leukaemia is a malignant leukocyte disorder with a high fatality rate, and current treatments for this disease are unsatisfactory. Therefore, new therapeutic strategies for leukaemia must be developed. Malaria parasite infection has been shown to be effective at combating certain neoplasms in animal experiments. This study is to demonstrate the anti-leukaemia activity of malaria parasite Plasmodium yoelii (P. yoelii) infection,. Methods In this study, the proportion of CD3, CD19, CD11b and Mac-3 cells was analysed by flow cytometry; the levels of IFN-γ and TNF-α in individual serum samples were measured by enzyme-linked immunosorbent assay, and the phagocytic activity of macrophages and natural killer (NK) cell activity were measured by flow cytometry. Results We found that P. yoelii infection significantly attenuated the growth of WEHI-3 cells in mice. In addition, tumor cell infiltration into the murine liver and spleen was markedly reduced. We also demonstrated that malaria parasite infection elicited anti-leukaemia activity by promoting immune responses, including increasing the surface markers of T cells (CD3) and B cells (CD19); decreasing the surface markers of monocytes (CD11b) and macrophages (Mac-3); inducing the secretion of IFN-γ and TNF-α; and increasing NK cell and macrophage activity. Conclusions Malaria parasite infection significantly decreases the number of myeloblasts and inhibits neoplasm proliferation in mice. In addition, malaria parasite infection inhibits murine leukaemia by promoting immune responses. Electronic supplementary material The online version of this article (10.1186/s40249-018-0433-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhen-Zhen Tong
- Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zheng-Ming Fang
- Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Qi Zhang
- Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yun Zhan
- Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yue Zhang
- Department of Immunology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Wan-Fang Jiang
- Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xiao Hou
- Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yong-Long Li
- Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ting Wang
- Department of Parasitology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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Coomes SM, Pelly VS, Kannan Y, Okoye IS, Czieso S, Entwistle LJ, Perez-Lloret J, Nikolov N, Potocnik AJ, Biró J, Langhorne J, Wilson MS. IFNγ and IL-12 Restrict Th2 Responses during Helminth/Plasmodium Co-Infection and Promote IFNγ from Th2 Cells. PLoS Pathog 2015; 11:e1004994. [PMID: 26147567 PMCID: PMC4493106 DOI: 10.1371/journal.ppat.1004994] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 06/02/2015] [Indexed: 12/19/2022] Open
Abstract
Parasitic helminths establish chronic infections in mammalian hosts. Helminth/Plasmodium co-infections occur frequently in endemic areas. However, it is unclear whether Plasmodium infections compromise anti-helminth immunity, contributing to the chronicity of infection. Immunity to Plasmodium or helminths requires divergent CD4+ T cell-driven responses, dominated by IFNγ or IL-4, respectively. Recent literature has indicated that Th cells, including Th2 cells, have phenotypic plasticity with the ability to produce non-lineage associated cytokines. Whether such plasticity occurs during co-infection is unclear. In this study, we observed reduced anti-helminth Th2 cell responses and compromised anti-helminth immunity during Heligmosomoides polygyrus and Plasmodium chabaudi co-infection. Using newly established triple cytokine reporter mice (Il4gfpIfngyfpIl17aFP635), we demonstrated that Il4gfp+ Th2 cells purified from in vitro cultures or isolated ex vivo from helminth-infected mice up-regulated IFNγ following adoptive transfer into Rag1–/– mice infected with P. chabaudi. Functionally, Th2 cells that up-regulated IFNγ were transcriptionally re-wired and protected recipient mice from high parasitemia. Mechanistically, TCR stimulation and responsiveness to IL-12 and IFNγ, but not type I IFN, was required for optimal IFNγ production by Th2 cells. Finally, blockade of IL-12 and IFNγ during co-infection partially preserved anti-helminth Th2 responses. In summary, this study demonstrates that Th2 cells retain substantial plasticity with the ability to produce IFNγ during Plasmodium infection. Consequently, co-infection with Plasmodium spp. may contribute to the chronicity of helminth infection by reducing anti-helminth Th2 cells and converting them into IFNγ-secreting cells. Approximately a third of the world’s population is burdened with chronic intestinal parasitic helminth infections, causing significant morbidities. Identifying the factors that contribute to the chronicity of infection is therefore essential. Co-infection with other pathogens, which is extremely common in helminth endemic areas, may contribute to the chronicity of helminth infections. In this study, we used a mouse model to test whether the immune responses to an intestinal helminth were impaired following malaria co-infection. These two pathogens induce very different immune responses, which, until recently, were thought to be opposing and non-interchangeable. This study identified that the immune cells required for anti-helminth responses are capable of changing their phenotype and providing protection against malaria. By identifying and blocking the factors that drive this change in phenotype, we can preserve anti-helminth immune responses during co-infection. Our studies provide fresh insight into how immune responses are altered during helminth and malaria co-infection.
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Affiliation(s)
- Stephanie M. Coomes
- Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom
| | - Victoria S. Pelly
- Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom
| | - Yashaswini Kannan
- Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom
| | - Isobel S. Okoye
- Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom
| | - Stephanie Czieso
- Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom
| | - Lewis J. Entwistle
- Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom
| | - Jimena Perez-Lloret
- Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom
| | - Nikolay Nikolov
- Division of Systems Biology, The Francis Crick Institute, London, United Kingdom
| | - Alexandre J. Potocnik
- Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom
| | - Judit Biró
- Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom
| | - Jean Langhorne
- Division of Parasitology, Mill Hill Laboratories, London, United Kingdom
| | - Mark S. Wilson
- Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom
- * E-mail:
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Thomé R, Bombeiro AL, Issayama LK, Rapôso C, Lopes SCP, da Costa TA, Di Gangi R, Ferreira IT, Longhini ALF, Oliveira ALR, da Cruz Höfling MA, Costa FTM, Verinaud L. Exacerbation of autoimmune neuro-inflammation in mice cured from blood-stage Plasmodium berghei infection. PLoS One 2014; 9:e110739. [PMID: 25329161 PMCID: PMC4201583 DOI: 10.1371/journal.pone.0110739] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Accepted: 09/16/2014] [Indexed: 01/24/2023] Open
Abstract
The thymus plays an important role shaping the T cell repertoire in the periphery, partly, through the elimination of inflammatory auto-reactive cells. It has been shown that, during Plasmodium berghei infection, the thymus is rendered atrophic by the premature egress of CD4+CD8+ double-positive (DP) T cells to the periphery. To investigate whether autoimmune diseases are affected after Plasmodium berghei NK65 infection, we immunized C57BL/6 mice, which was previously infected with P. berghei NK65 and treated with chloroquine (CQ), with MOG35-55 peptide and the clinical course of Experimental Autoimmune Encephalomyelitis (EAE) was evaluated. Our results showed that NK65+CQ+EAE mice developed a more severe disease than control EAE mice. The same pattern of disease severity was observed in MOG35-55-immunized mice after adoptive transfer of P. berghei-elicited splenic DP-T cells. The higher frequency of IL-17+- and IFN-γ+-producing DP lymphocytes in the Central Nervous System of these mice suggests that immature lymphocytes contribute to disease worsening. To our knowledge, this is the first study to integrate the possible relationship between malaria and multiple sclerosis through the contribution of the thymus. Notwithstanding, further studies must be conducted to assert the relevance of malaria-induced thymic atrophy in the susceptibility and clinical course of other inflammatory autoimmune diseases.
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Affiliation(s)
- Rodolfo Thomé
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - André Luis Bombeiro
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Luidy Kazuo Issayama
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Catarina Rapôso
- Department of Histology and Embryology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Stefanie Costa Pinto Lopes
- Department of Genetics, Evolution and Bioagents, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Thiago Alves da Costa
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Rosária Di Gangi
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Isadora Tassinari Ferreira
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | | | | | | | | | - Liana Verinaud
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, Brazil
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Wilmore JR, Maue AC, Lefebvre JS, Haynes L, Rochford R. AcutePlasmodium chabaudiInfection Dampens Humoral Responses to a Secondary T-Dependent Antigen but Enhances Responses to a Secondary T-Independent Antigen. J I 2013; 191:4731-9. [DOI: 10.4049/jimmunol.1301450] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Chen L, He Z, Qin L, Li Q, Shi X, Zhao S, Chen L, Zhong N, Chen X. Antitumor effect of malaria parasite infection in a murine Lewis lung cancer model through induction of innate and adaptive immunity. PLoS One 2011; 6:e24407. [PMID: 21931708 PMCID: PMC3170332 DOI: 10.1371/journal.pone.0024407] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 08/08/2011] [Indexed: 12/22/2022] Open
Abstract
Background Lung cancer is the most common malignancy in humans and its high fatality means that no effective treatment is available. Developing new therapeutic strategies for lung cancer is urgently needed. Malaria has been reported to stimulate host immune responses, which are believed to be efficacious for combating some clinical cancers. This study is aimed to provide evidence that malaria parasite infection is therapeutic for lung cancer. Methodology/Principal Findings Antitumor effect of malaria infection was examined in both subcutaneously and intravenously implanted murine Lewis lung cancer (LLC) model. The results showed that malaria infection inhibited LLC growth and metastasis and prolonged the survival of tumor-bearing mice. Histological analysis of tumors from mice infected with malaria revealed that angiogenesis was inhibited, which correlated with increased terminal deoxynucleotidyl transferase-mediated (TUNEL) staining and decreased Ki-67 expression in tumors. Through natural killer (NK) cell cytotoxicity activity, cytokine assays, enzyme-linked immunospot assay, lymphocyte proliferation, and flow cytometry, we demonstrated that malaria infection provided anti-tumor effects by inducing both a potent anti-tumor innate immune response, including the secretion of IFN-γ and TNF-α and the activation of NK cells as well as adaptive anti-tumor immunity with increasing tumor-specific T-cell proliferation and cytolytic activity of CD8+ T cells. Notably, tumor-bearing mice infected with the parasite developed long-lasting and effective tumor-specific immunity. Consequently, we found that malaria parasite infection could enhance the immune response of lung cancer DNA vaccine pcDNA3.1-hMUC1 and the combination produced a synergistic antitumor effect. Conclusions/Significance Malaria infection significantly suppresses LLC growth via induction of innate and adaptive antitumor responses in a mouse model. These data suggest that the malaria parasite may provide a novel strategy or therapeutic vaccine vector for anti-lung cancer immune-based therapy.
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MESH Headings
- Adaptive Immunity/immunology
- Animals
- Apoptosis
- Cancer Vaccines/immunology
- Carcinoma, Lewis Lung/blood supply
- Carcinoma, Lewis Lung/immunology
- Carcinoma, Lewis Lung/parasitology
- Carcinoma, Lewis Lung/surgery
- Cell Proliferation
- Cytokines/biosynthesis
- Cytotoxicity, Immunologic/immunology
- Dendritic Cells/immunology
- Disease Models, Animal
- Immunity, Innate/immunology
- Killer Cells, Natural/immunology
- Lymphocytes, Tumor-Infiltrating/immunology
- Malaria/parasitology
- Mice
- Neoplasm Metastasis
- Neovascularization, Pathologic/immunology
- Neovascularization, Pathologic/pathology
- Parasites/immunology
- Plasmodium yoelii/immunology
- Th1 Cells/immunology
- Vaccines, DNA/immunology
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Affiliation(s)
- Lili Chen
- Center for Infection and Immunity, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- CAS-FS Biotech and Pharmaceutical Center, Chinese Academy of Sciences, Foshan, China
| | - Zhengxiang He
- Center for Infection and Immunity, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- CAS-FS Biotech and Pharmaceutical Center, Chinese Academy of Sciences, Foshan, China
| | - Li Qin
- Center for Infection and Immunity, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- CAS-FS Biotech and Pharmaceutical Center, Chinese Academy of Sciences, Foshan, China
| | - Qinyan Li
- Center for Infection and Immunity, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- CAS-FS Biotech and Pharmaceutical Center, Chinese Academy of Sciences, Foshan, China
| | - Xibao Shi
- Center for Infection and Immunity, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Siting Zhao
- Center for Infection and Immunity, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Ling Chen
- Center for Infection and Immunity, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Nanshan Zhong
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
- * E-mail: (XC) (NZ); (NZ) (XC)
| | - Xiaoping Chen
- Center for Infection and Immunity, State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- CAS-FS Biotech and Pharmaceutical Center, Chinese Academy of Sciences, Foshan, China
- * E-mail: (XC) (NZ); (NZ) (XC)
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Castillo-Méndez SI, Zago CA, Sardinha LR, Freitas do Rosário AP, Alvarez JM, D'Império Lima MR. Characterization of the spleen B-cell compartment at the early and late blood-stage Plasmodium chabaudi malaria. Scand J Immunol 2007; 66:309-19. [PMID: 17635808 DOI: 10.1111/j.1365-3083.2007.01972.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [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: 11/28/2022]
Abstract
Polyclonal B-cell activation is a feature of the early spleen cell response to blood-stage Plasmodium chabaudi malaria. Immunity to blood-stage malaria is guaranteed by the generation of B cells able to produce parasite-specific antibodies mainly from the immunoglobulin (Ig)G2a isotype. In the present study, we characterized the spleen B-cell compartment during blood-stage P. chabaudi infection. The numbers of B220(+) and B220(LOW) CD138(+) (plasma) cells increased sharply between days 4 and 7 post-infection (p.i.). At this time B220(+) cells expressed surface (s)IgM, but nearly all B220(LOW) CD138(+) cells showed concomitantly intracellular (i)IgM and IgG2a. Both follicular and marginal zone B cells were activated expressing high amounts of CD69. At day 40 p.i., B220(LOW) CD138(+) cell population was still increased but, differently from acute infection, 61.1% of these cells were positive for iIgG2a while only 14.2% expressed iIgM. Moreover, at days 20 and 40 p.i., 29.2% and 13.0% of B220(+) cells expressed sIgG2a, respectively. According to cell size and expression of CD80, CD86, CD11b, CD44 and CD38, B220(+) sIgG2a(+) cells had a phenotype characteristic of activated/memory B cells. Furthermore, 14.1% of B220(+) sIgG2a(+) cells at day 30 p.i. expressed a marginal zone B-cell phenotype. Importantly, B cells from 40-day-infected mice were very efficient in presenting parasite antigens leading to proliferation of both CD4(+) and CD8(+) cells. Our results contribute for understanding the dynamics of B cells during P. chabaudi infection, underlying the mechanisms of antigen presentation and antibody production, which are essential for the acquisition of protective immunity against malaria.
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Affiliation(s)
- S I Castillo-Méndez
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
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Elias RM, Sardinha LR, Bastos KRB, Zago CA, da Silva APF, Alvarez JM, Lima MRD. Role of CD28 in polyclonal and specific T and B cell responses required for protection against blood stage malaria. J Immunol 2005; 174:790-9. [PMID: 15634900 DOI: 10.4049/jimmunol.174.2.790] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The role of B7/CD28 costimulatory pathway in the polyclonal and specific lymphocyte activation induced by blood stages of Plasmodium chabaudi AS was investigated in CD28 gene knockout (CD28(-/-)) and C57BL/6 (CD28(+/+)) mice. Analysis of the spleen during the acute infection revealed a similar increase in T and B cell populations in both groups of mice. Moreover, CD28(-/-) mice were able to develop a polyclonal IgM response to P. chabaudi. On the contrary, the polyclonal IgG2a response was markedly reduced in the absence of CD28. Production of IFN-gamma; up-regulation of CD69, CD40L, CD95 (Fas), and CD95L (Fas ligand); and induction of apoptosis were also affected by the lack of CD28. Interestingly, the ability to control the first parasitemia peak was not compromised in acutely infected CD28(-/-) mice, but CD28(-/-) mice failed to eradicate the parasites that persisted in the blood for >3 mo after infection. In addition, drug-cured CD28(-/-) mice were unable to generate memory T cells, develop an anamnesic IgG response, or eliminate the parasites from a secondary challenge. The incapacity of CD28(-/-) mice to acquire a full protective immunity to P. chabaudi correlated with an impaired production of specific IgG2a. Moreover, reinfected CD28(-/-) mice were protected by the adoptive transfer of serum from reinfected CD28(+/+) mice containing specific IgG2a. Our results demonstrate that the polyclonal lymphocyte response is only partially affected by the absence of CD28, but this coreceptor is essential to generate specific T and B cell responses required for complete protection against P. chabaudi malaria.
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Affiliation(s)
- Rosa M Elias
- Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
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