A successful cellular immune response to Toxoplasma gondii and many other intracellular pathogens involves a delicate balance between the actions of IL-12, a pro- inflammatory innate cytokine triggered by the parasite and IL-10, a regulatory cytokine produced by adaptive T cells to prevent immunopathology. The overall goal of this proposal is to explore how IL-12 controls the generation and persistence of parasite- reactive CD8 effector and memory cells required for protective immunity and how IL-10 acts in a novel autocrine fashion to avert tissue damage. Using a new mouse model with T-cell lineage specific interference in IL-10 signaling, we have obtained evidence that IL- 10 activation of a T-cell intrinsic anti-inflammatory response is required to prevent morbidity and mortality during T. gondii infection. We will use this transgenic and other knockout mouse models to elucidate the kinetics, regulation and functional consequences of IL-10 responsiveness during the Th1 response to T. gondii and explore a novel mechanism for how IL-10 cell-autonomously restrains Th1 cytokine responses. We have recently described four subpopulations of CD8 cells induced by immunization with the cps-vaccine strain of T. gondii and have published evidence that IL-12 is critically required for the generation of effector CD8 T cells expressing IFN3, granzyme B and KLRG1. In collaboration with Dr. Hidde Ploegh's laboratory at MIT, we have identified the first Kb-restricted CTL epitope from T. gondii and our collaborators have also developed a cloned mouse line bearing monoclonal naove CD8 T cells reactive to this Kb- restricted T. gondii antigen. Using these new mouse and immunological reagents, we will elucidate the cytokine requirements, lineage relationships and functional significance of the heterogenous CD8 T cell subsets induced by T. gondii vaccination and infection. We will critically assess the costs and benefits of IL-12 signaling on the immediate and recall CD8 protective response to re-infection.
Disease caused by parasitic protozoa and other intracellular microbial agents are major causes of mortality and morbidity worldwide. Morbidity and mortality may be caused by immunodeficiency leading to tissue destruction by the parasites or these may result from an overzealous or dysregulated immune response. The studies proposed here will provide new insights into how potentially pathogenic Th1 cells are restrained and how protective CD8 T cells are generated and maintained over the long term, specifically with respect to how cytokines control these immune processes. Insights from these investigations may become useful for vaccination strategies and the management of inflammatory and infectious diseases.
|Marple, Andrew; Wu, Wenhui; Shah, Suhagi et al. (2017) Cutting Edge: Helminth Coinfection Blocks Effector Differentiation of CD8 T Cells through Alternate Host Th2- and IL-10-Mediated Responses. J Immunol 198:634-639|
|Rivera, Amariliz; Siracusa, Mark C; Yap, George S et al. (2016) Innate cell communication kick-starts pathogen-specific immunity. Nat Immunol 17:356-63|
|Shah, Suhagi; Grotenbreg, Gijsbert M; Rivera, Amariliz et al. (2015) An extrafollicular pathway for the generation of effector CD8(+) T cells driven by the proinflammatory cytokine, IL-12. Elife 4:|
|Cohen, Sara B; Smith, Norah L; McDougal, Courtney et al. (2015) Beta-catenin signaling drives differentiation and proinflammatory function of IRF8-dependent dendritic cells. J Immunol 194:210-22|
|Zhao, Yanlin; Marple, Andrew H; Ferguson, David J P et al. (2014) Avirulent strains of Toxoplasma gondii infect macrophages by active invasion from the phagosome. Proc Natl Acad Sci U S A 111:6437-42|
|Zhao, Yanlin; Yap, George S (2014) Toxoplasma's arms race with the host interferon response: a ménage à trois of ROPs. Cell Host Microbe 15:517-8|
|Patil, Veerupaxagouda; Zhao, Yanlin; Shah, Suhagi et al. (2014) Co-existence of classical and alternative activation programs in macrophages responding to Toxoplasma gondii. Int J Parasitol 44:161-4|
|Salgame, Padmini; Yap, George S; Gause, William C (2013) Effect of helminth-induced immunity on infections with microbial pathogens. Nat Immunol 14:1118-1126|
|Yap, George S; Rivera, Amariliz (2012) IFN-ýý signals a changing of the guards. Immunity 36:904-6|
|Gaddi, Pamela J; Crane, Meredith J; Kamanaka, Masahito et al. (2012) IL-10 mediated regulation of liver inflammation during acute murine cytomegalovirus infection. PLoS One 7:e42850|
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