scholarly journals Effector CD8+ T Lymphocytes against Liver Stages of Plasmodium yoelii Do Not Require Gamma Interferon for Antiparasite Activity

2008 ◽  
Vol 76 (8) ◽  
pp. 3628-3631 ◽  
Author(s):  
Sumana Chakravarty ◽  
G. Christian Baldeviano ◽  
Michael G. Overstreet ◽  
Fidel Zavala

ABSTRACT The protective immune response against liver stages of the malaria parasite critically requires CD8+ T cells. Although the nature of the effector mechanism utilized by these cells to repress parasite development remains unclear, a critical role for gamma interferon (IFN-γ) has been widely assumed based on circumstantial evidence. However, the requirement for CD8+ T-cell-mediated IFN-γ production in protective immunity to this pathogen has not been directly tested. In this report, we use an adoptive transfer strategy with circumsporozoite (CS) protein-specific transgenic T cells to examine the role of CD8+ T-cell-derived IFN-γ production in Plasmodium yoelii-infected mice. We show that despite a marginal reduction in the expansion of naive IFN-γ-deficient CS-specific transgenic T cells, their antiparasite activity remains intact. Further, adoptively transferred IFN-γ-deficient CD8+ T cells were as efficient as their wild-type counterparts in limiting parasite growth in naive mice. Taken together, these studies demonstrate that IFN-γ secretion by CS-specific CD8+ T cells is not essential to protect mice against live sporozoite challenge.

2004 ◽  
Vol 72 (8) ◽  
pp. 4432-4438 ◽  
Author(s):  
Xisheng Wang ◽  
Hoil Kang ◽  
Takane Kikuchi ◽  
Yasuhiro Suzuki

ABSTRACT We previously showed the requirement of both T cells and gamma interferon (IFN-γ)-producing non-T cells for the genetic resistance of BALB/c mice to the development of toxoplasmic encephalitis (TE). In order to define the role of IFN-γ production and the perforin-mediated cytotoxicity of T cells in this resistance, we obtained immune T cells from spleens of infected IFN-γ knockout (IFN-γ−/−), perforin knockout (PO), and wild-type BALB/c mice and transferred them into infected and sulfadiazine-treated athymic nude mice, which lack T cells but have IFN-γ-producing non-T cells. Control nude mice that had not received any T cells developed severe TE and died after discontinuation of sulfadiazine treatment due to the reactivation of infection. Animals that had received immune T cells from either wild-type or PO mice did not develop TE and survived. In contrast, nude mice that had received immune T cells from IFN-γ−/− mice developed severe TE and died as early as control nude mice. T cells obtained from the spleens of animals that had received either PO or wild-type T cells produced large amounts of IFN-γ after stimulation with Toxoplasma gondii antigens in vitro. In addition, the amounts of IFN-γ mRNA expressed in the brains of PO T-cell recipients did not differ from those in wild-type T-cell recipients. Furthermore, PO mice did not develop TE after infection, and their IFN-γ production was equivalent to or higher than that of wild-type animals. These results indicate that IFN-γ production, but not perforin-mediated cytotoxic activity, by T cells is required for the prevention of TE in genetically resistant BALB/c mice.


2013 ◽  
Vol 81 (11) ◽  
pp. 4171-4181 ◽  
Author(s):  
Laura A. Cooney ◽  
Megha Gupta ◽  
Sunil Thomas ◽  
Sebastian Mikolajczak ◽  
Kimberly Y. Choi ◽  
...  

ABSTRACTVaccination with a single dose of genetically attenuated malaria parasites can induce sterile protection against sporozoite challenge in the rodentPlasmodium yoeliimodel. Protection is dependent on CD8+T cells, involves perforin and gamma interferon (IFN-γ), and is correlated with the expansion of effector memory CD8+T cells in the liver. Here, we have further characterized vaccine-induced changes in the CD8+T cell phenotype and demonstrated significant upregulation of CD11c on CD3+CD8b+T cells in the liver, spleen, and peripheral blood. CD11c+CD8+T cells are predominantly CD11ahiCD44hiCD62L−, indicative of antigen-experienced effector cells. Followingin vitrorestimulation with malaria-infected hepatocytes, CD11c+CD8+T cells expressed inflammatory cytokines and cytotoxicity markers, including IFN-γ, tumor necrosis factor alpha (TNF-α), interleukin-2 (IL-2), perforin, and CD107a. CD11c−CD8+T cells, on the other hand, expressed negligible amounts of all inflammatory cytokines and cytotoxicity markers tested, indicating that CD11c marks multifunctional effector CD8+T cells. Coculture of CD11c+, but not CD11c−, CD8+T cells with sporozoite-infected primary hepatocytes significantly inhibited liver-stage parasite development. Tetramer staining for the immunodominant circumsporozoite protein (CSP)-specific CD8+T cell epitope demonstrated that approximately two-thirds of CSP-specific cells expressed CD11c at the peak of the CD11c+CD8+T cell response, but CD11c expression was lost as the CD8+T cells entered the memory phase. Further analyses showed that CD11c+CD8+T cells are primarily KLRG1+CD127−terminal effectors, whereas all KLRG1−CD127+memory precursor effector cells are CD11c−CD8+T cells. Together, these results suggest that CD11c marks a subset of highly inflammatory, short-lived, antigen-specific effector cells, which may play an important role in eliminating infected hepatocytes.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 77-77
Author(s):  
Hong Xu ◽  
Jun Yan ◽  
Ziqiang Zhu ◽  
Yiming Huang ◽  
Yujie Wen ◽  
...  

Abstract Abstract 77 Adaptive immunity, especially T cells, has long been believed to be the dominant immune barrier in allogeneic transplantation. Targeting host T cells significantly reduces conditioning for bone marrow cell (BMC) engraftment. Innate immunity has been recently shown to pose a significant barrier in solid organ transplantation, but has not been addressed in bone marrow transplantation (BMT). Using T cell deficient (TCR-β/δ−/−) or T and B cell deficient (Rag−/−) mice, we found that allogeneic BMC rejection occurred early before the time required for T cell activation and was T- and B-cell independent, suggesting an effector role for innate immune cells in BMC rejection. Therefore, we hypothesized that by controlling both innate and adaptive immunity, the donor BMC would have a window of advantage to engraft. Survival of BMC in vivo was significantly improved by depleting recipient macrophages and/or NK cells, but not neutrophils. Moreover, depletion of macrophages and NK cells in combination with co-stimulatory blockade with anti-CD154 and rapamycin as a novel form of conditioning resulted in 100% allogeneic engraftment without any irradiation and T cell depletion. Donor chimerism remained stable and durable up to 6 months. Moreover, specific Vβ5½ and Vβ11 clonal deletion was detected in host CD4+ T cells in chimeras, indicating central tolerance to donor alloantigens. Whether and how the innate immune system recognizes or responds to allogeneic BMCs remains unknown. Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system. The signaling function of TLR depends on intracellular adaptors. The adaptor MyD88 transmits signals emanating from all TLR, except TLR3 while TRIF specifically mediates TLR3 and TLR4 signaling via type 1 IFN. To further determine the innate signaling pathways in allogeneic BMC rejection, B6 background (H2b) MyD88−/− and TRIF−/− mice were conditioned with anti-CD154/rapamycin plus 100 cGy total body irradiation and transplanted with 15 × 106 BALB/c (H2d) BMC. Only 33.3% of MyD88−/− recipients engrafted at 1 month, resembling outcomes for wild-type B6 mice. In contrast, 100% of TRIF−/− mice engrafted. The level of donor chimerism in TRIF−/− mice was 5.1 ± 0.6% at one month, significantly higher than in MyD88−/− and wild-type B6 controls (P < 0.005). To determine the mechanism of innate signaling in BMC rejection, we examined whether TRIF linked TLR3 or TLR4 is the key pattern recognition receptor involved in BMC recognition. To this end, TLR3−/− and TLR4−/− mice were transplanted with BALB/c BMC with same conditioning. None of the TLR3−/− mice engrafted. In contrast, engraftment was achieved in 100% of TLR4−/− mice up to 6 months follow up. Taken together, these results suggest that rejection of allogeneic BMC is uniquely dependent on the TLR4/TRIF signaling pathway. Thus, our results clearly demonstrate a previously unappreciated role for innate immunity in allogeneic BMC rejection. Our current findings are distinct from prior reports demonstrating a critical role of MyD88 in rejection of allogeneic skin grafts and lung, and may reflect unique features related to BMC. The findings of the role of innate immunity in BMC rejection would lead to revolutionary changes in our understanding and management of BMT. This would be informative in design of more specific innate immune targeted conditioning proposals in BMT to avoid the toxicity. Disclosures: Bozulic: Regenerex LLC: Employment. Ildstad:Regenerex LLC: Equity Ownership.


Blood ◽  
2002 ◽  
Vol 100 (8) ◽  
pp. 2899-2907 ◽  
Author(s):  
Duncan Howie ◽  
Susumo Okamoto ◽  
Svend Rietdijk ◽  
Kareem Clarke ◽  
Ninghai Wang ◽  
...  

CD150 (signaling lymphocyte activation molecule [SLAM]) is a self-ligand cell surface glycoprotein expressed on T cells, B cells, macrophages, and dendritic cells. To further explore the role of CD150 signaling in costimulation and TH1 priming we have generated a panel of rat antimouse CD150 monoclonal antibodies. CD150 cell surface expression is up-regulated with rapid kinetics in activated T cells and lipopolysaccharide/interferon γ (IFN-γ)–activated macrophages. Anti-CD150 triggering induces strong costimulation of T cells triggered through CD3. DNA synthesis of murine T cells induced by anti-CD150 is not dependent on SLAM-associated protein (SAP, SH2D1A), because anti-CD150 induces similar levels of DNA synthesis in SAP−/− T cells. Antibodies to CD150 also enhance IFN-γ production both in wild-type and SAP−/− T cells during primary stimulation. The level of IFN-γ production is higher in SAP−/− T cells than in wild-type T cells. Anti-CD150 antibodies also synergize with interleukin 12 (IL-12) treatment in up-regulation of IL-12 receptor β2 mRNA during TH1 priming, and inhibit primary TH2 polarization in an IFN-γ–dependent fashion. Cross-linking CD150 on CD4 T cells induces rapid serine phosphorylation of Akt/PKB. We speculate that this is an important pathway contributing to CD150-mediated T-cell proliferation.


2018 ◽  
Vol 86 (7) ◽  
pp. e00143-18 ◽  
Author(s):  
Taylor B. Poston ◽  
Catherine M. O'Connell ◽  
Jenna Girardi ◽  
Jeanne E. Sullivan ◽  
Uma M. Nagarajan ◽  
...  

ABSTRACTCD4 T cells and antibody are required for optimal acquired immunity toChlamydia muridarumgenital tract infection, and T cell-mediated gamma interferon (IFN-γ) production is necessary to clear infection in the absence of humoral immunity. However, the role of T cell-independent immune responses during primary infection remains unclear. We investigated this question by inoculating wild-type and immune-deficient mice withC. muridarumCM001, a clonal isolate capable of enhanced extragenital replication. Genital inoculation of wild-type mice resulted in transient dissemination to the lungs and spleen that then was rapidly cleared from these organs. However, CM001 genital infection proved lethal forSTAT1−/−andIFNG−/−mice, in which IFN-γ signaling was absent, and forRag1−/−mice, which lacked T and B cells and in which innate IFN-γ signaling was retained. In contrast, B cell-deficient muMT mice, which can generate a Th1 response, and T cell-deficient mice with intact B cell and innate IFN-γ signaling survived. These data collectively indicate that IFN-γ prevents lethal CM001 dissemination in the absence of T cells and suggests a B cell corequirement. Adoptive transfer of convalescent-phase immune serum but not naive IgM toRag1−/−mice infected with CM001 significantly increased the survival time, while transfer of naive B cells completely rescuedRag1−/−mice from CM001 lethality. Protection was associated with a significant reduction in the lung chlamydial burden of genitally infected mice. These data reveal an important cooperation between T cell-independent B cell responses and innate IFN-γ in chlamydial host defense and suggest that interactions between T cell-independent antibody and IFN-γ are essential for limiting extragenital dissemination.


1998 ◽  
Vol 72 (8) ◽  
pp. 6637-6645 ◽  
Author(s):  
Adrian Bot ◽  
Simona Bot ◽  
Constantin A. Bona

ABSTRACT During secondary immune responses to influenza virus, virus-specific T memory cells are a major source of gamma interferon (IFN-γ). We assessed the contribution of IFN-γ to heterologous protection against the A/WSN/33 (H1N1) virus of wild-type and IFN-γ−/− mice previously immunized with the A/HK/68 (H3N2) virus. The IFN-γ−/− mice displayed significantly reduced survival rates subsequent to a challenge with various doses of the A/WSN/33 virus. This was associated with an impaired ability of the IFN-γ−/− mice to completely clear the pulmonary virus by day 7 after the challenge, although significant reduction of the virus titers was noted. However, the IFN-γ−/− mice developed type A influenza virus cross-reactive cytotoxic T lymphocytes (CTLs) similar to the wild-type mice, as demonstrated by both cytotoxicity and a limiting-dilution assay for the estimation of CTL precursor frequency. The pulmonary recruitment of T cells in IFN-γ−/− mice was not dramatically affected, and the percentage of CD4+ and CD8+ T cells was similar to that of wild-type mice. The T cells from IFN-γ−/− mice did not display a significant switch toward a Th2 profile. Furthermore, the IFN-γ−/− mice retained the ability to mount significant titers of WSN and HK virus-specific hemagglutination-inhibiting antibodies. Together, these results are consistent with a protective role of IFN-γ during the heterologous response against influenza virus independently of the generation and local recruitment of cross-reactive CTLs.


1998 ◽  
Vol 66 (2) ◽  
pp. 830-834 ◽  
Author(s):  
Ricardo E. Tascon ◽  
Evangelos Stavropoulos ◽  
Katalin V. Lukacs ◽  
M. Joseph Colston

ABSTRACT The role of CD8 T cells in controlling Mycobacterium tuberculosis infections in mice was confirmed by comparing the levels of growth of the organism in control, major histocompatibility complex class II knockout, and athymic mice and by transferring T-cell populations into athymic mice. By using donor mice which were incapable of making gamma interferon (IFN-γ), it was shown that IFN-γ production was essential for CD8 cell mediation of protective immunity against M. tuberculosis.


2019 ◽  
Vol 87 (10) ◽  
Author(s):  
Bhavna Chawla ◽  
Babita Mahajan ◽  
Miranda Oakley ◽  
Victoria F. Majam ◽  
Arnel Belmonte ◽  
...  

ABSTRACT The development of effective malaria vaccines is hampered by incomplete understanding of the immunological correlates of protective immunity. Recently, the moderate clinical efficacy of the Plasmodium falciparum circumsporozoite protein (CSP)-based RTS,S/AS01E vaccine in phase 3 studies highlighted the urgency to design and test more efficacious next-generation malaria vaccines. In this study, we report that immunization with recombinant CSP from Plasmodium yoelii (rPyCSP), when delivered in Montanide ISA 51, induced sterilizing immunity against sporozoite challenge in C57BL/6 and BALB/c strains of mice. This immunity was antibody dependent, as evidenced by the complete loss of immunity in B-cell-knockout (KO) mice and by the ability of immune sera to neutralize sporozoite infectivity in mice. Th2-type isotype IgG1 antibody levels were associated with protective immunity. The fact that immunized gamma interferon (IFN-γ)-KO mice and wild-type (WT) mice have similar levels of protective immunity and the absence of IFN-γ-producing CD4+ and CD8+ T cells in protected mice, as shown by flow cytometry, indicate that the immunity is IFN-γ independent. Protection against sporozoite challenge correlated with higher frequencies of CD4+ T cells that express interleukin-2 (IL-2), IL-4, and tumor necrosis factor alpha (TNF-α). In the RTS,S study, clinical immunity was associated with higher IgG levels and frequencies of IL-2- and TNF-α-producing CD4+ T cells. The other hallmarks of immunity in our study included an increased number of follicular B cells but a loss in follicular T helper cells. These results provide an excellent model system to evaluate the efficacy of novel adjuvants and vaccine dosage and determine the correlates of immunity in the search for superior malaria vaccine candidates.


2002 ◽  
Vol 70 (9) ◽  
pp. 5208-5215 ◽  
Author(s):  
Chad Steele ◽  
Mingquan Zheng ◽  
Erana Young ◽  
Luis Marrero ◽  
Judd E. Shellito ◽  
...  

ABSTRACT Although a clear relationship between αβ T-cell receptor-positive (αβ-TCR+) CD4+ T cells and susceptibility to Pneumocystis carinii infection exists, the role of other T-cell subsets is less clearly defined. Previous studies have shown that γδ-TCR+ T cells infiltrate into the lung during P. carinii pneumonia. Therefore, the present study examined the role of γδ-TCR+ T cells in host defense against P. carinii pneumonia. C57BL/6 (control) and B6.129P2-Tcrdtm1Mom (γδ-TCR+ T-cell-deficient) mice were inoculated intratracheally with P. carinii. At specific time points, mice were sacrificed and analyzed for P. carinii burden, T-cell subsets, and cytokine levels in lung tissue. Analysis of P. carinii burden showed a more rapid and complete resolution of infection in γδ-TCR+ T-cell-deficient mice than in C57BL/6 controls. This augmented resolution was associated with elevated gamma interferon (IFN-γ) levels in bronchoalveolar lavage fluid predominantly produced by CD8+ T cells, as well as an increased recruitment of CD8+ T cells in general. In separate experiments, neutralization of IFN-γ or depletion of CD8+ T cells early during infection abolished the augmented resolution previously observed in γδ-TCR+ T-cell-deficient mice. These results show that the presence of γδ-TCR+ T cells modulates host susceptibility to P. carinii pneumonia through interactions with pulmonary CD8+ T cells and tissue production of IFN-γ.


2019 ◽  
Vol 87 (6) ◽  
Author(s):  
Hui Lin ◽  
Conghui He ◽  
John J. Koprivsek ◽  
Jianlin Chen ◽  
Zhiguang Zhou ◽  
...  

ABSTRACTThe genital tract pathogenChlamydia trachomatisis frequently detected in the gastrointestinal tract, but the host immunity that regulates chlamydial colonization in the gut remains unclear. In aChlamydia muridarum-C57 mouse model, chlamydial organisms are cleared from the genital tract in ∼4 weeks, but the genital organisms can spread to the gastrointestinal tract. We found that the gastrointestinal chlamydial organisms were cleared from the small intestine by day 28, paralleling their infection course in the genital tract, but persisted in the large intestine for long periods. Mice deficient in α/β T cells or CD4+T cells but not CD8+T cells showed chlamydial persistence in the small intestine, indicating a critical role for CD4+T cells in clearingChlamydiafrom the small intestine. The CD4+T cell-dependent clearance is likely mediated by gamma interferon (IFN-γ), since mice deficient in IFN-γ but not interleukin 22 (IL-22) signaling pathways rescued chlamydial colonization in the small intestine. Furthermore, exogenous IFN-γ was sufficient for clearingChlamydiafrom the small intestine but not the large intestine. Mice deficient in developingChlamydia-specific Th1 immunity showed chlamydial persistence in the small intestine. Finally, IFN-γ-producing CD4+but not CD8+T cells from immunized donor mice were sufficient for eliminatingChlamydiafrom the small intestine but not the large intestine of recipient mice. Thus, we have demonstrated a critical role for Th1 immunity in clearingChlamydiafrom the small intestine but not the large intestine, indicating that chlamydial colonization in different regions of the gastrointestinal tract is regulated by distinct immune mechanisms.


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