Project description:Comparison of two Chlamydia-specific CD4 T cells that are dependent on iNOS to terminate Chlamydia replication in epithelial cells to two Chlamydia-specific CD4 T cells that are iNOS-independent: Chlamydia trachomatis urogenital serovars replicate predominately in epithelial cells lining the reproductive tract. This tissue tropism poses a unique challenge for the host immune system and vaccine development. Studies utilizing the Chlamydia muridarum mouse model have shown that CD4 T cells are critical and sufficient to clear primary genital tract infections. In vitro studies have shown that CD4 T cells terminate the infection in epithelial cells by up regulating epithelial iNOS transcription and nitric oxide production via IFN-gamma and T cell-epithelial cell interactions mediated by LFA-1-ICAM-1. This mechanism however is not critical as iNOS-deficient mice clear infections normally, and IFN-gamma deficient mice clear 99.9% of the infection with near normal kinetics. We recently showed that a subset of Chlamydia-specific CD4 T cell clones were able to terminate replication in epithelial cells using a mechanism that was independent of iNOS and IFN-gamma. That mechanism did not require physical lysis of infected cells, but instead required T cell degranulation. In this study we advanced that work using gene expression microarrays to compare CD4 T cell clones that are able to terminate epithelial replication via an iNOS-independent mechanism to iNOS-dependent CD4 T cell clones. Micro array experiments showed that Plac8 was differentially expressed by the T cell clones having the iNOS-independent mechanism. Plac8-deficient mice had significantly delayed clearance of C. muridarum genital tract infections, and that the large majority of Plac8-deficient mice treated with the iNOS-inhibitor N-monomethyl-L-arginine (MLA) were unable to resolve a C. muridarum genital tract infection over 8 weeks. These results demonstrate that there are two independent and redundant T cell mechanisms for clearing C. muridarum genital tract infections; one mechanism dependent on iNOS, the other mechanism dependent on Plac8. While T cells subsets have been defined by cytokine profiles, there are important subdivisions by effector functions, in this case CD4Plac8. Gene expression study using 4 experimental groups with 4 replicates each.
Project description:Comparison of two Chlamydia-specific CD4 T cells that are dependent on iNOS to terminate Chlamydia replication in epithelial cells to two Chlamydia-specific CD4 T cells that are iNOS-independent: Chlamydia trachomatis urogenital serovars replicate predominately in epithelial cells lining the reproductive tract. This tissue tropism poses a unique challenge for the host immune system and vaccine development. Studies utilizing the Chlamydia muridarum mouse model have shown that CD4 T cells are critical and sufficient to clear primary genital tract infections. In vitro studies have shown that CD4 T cells terminate the infection in epithelial cells by up regulating epithelial iNOS transcription and nitric oxide production via IFN-gamma and T cell-epithelial cell interactions mediated by LFA-1-ICAM-1. This mechanism however is not critical as iNOS-deficient mice clear infections normally, and IFN-gamma deficient mice clear 99.9% of the infection with near normal kinetics. We recently showed that a subset of Chlamydia-specific CD4 T cell clones were able to terminate replication in epithelial cells using a mechanism that was independent of iNOS and IFN-gamma. That mechanism did not require physical lysis of infected cells, but instead required T cell degranulation. In this study we advanced that work using gene expression microarrays to compare CD4 T cell clones that are able to terminate epithelial replication via an iNOS-independent mechanism to iNOS-dependent CD4 T cell clones. Micro array experiments showed that Plac8 was differentially expressed by the T cell clones having the iNOS-independent mechanism. Plac8-deficient mice had significantly delayed clearance of C. muridarum genital tract infections, and that the large majority of Plac8-deficient mice treated with the iNOS-inhibitor N-monomethyl-L-arginine (MLA) were unable to resolve a C. muridarum genital tract infection over 8 weeks. These results demonstrate that there are two independent and redundant T cell mechanisms for clearing C. muridarum genital tract infections; one mechanism dependent on iNOS, the other mechanism dependent on Plac8. While T cells subsets have been defined by cytokine profiles, there are important subdivisions by effector functions, in this case CD4Plac8.
Project description:The purpose of this study was to compare CD4 T cell gene expression from the female reproductive tracts (FRTs) of mice infected vaginally with Chlamydia muridarum in wild-type, T-bet deficient, and RORgt mutant mice.
Project description:The T cell response to Chlamydia genital tract infections in humans and mice is unusual in that the majority of antigen-specific CD8 T cells are not restricted by HLA/MHC class I and therefore have been referred to as “unrestricted” or “atypical”. We previously reported that a subset of unrestricted murine Chlamydia-specific CD8 T cells had an unusual cytokine polarization pattern that included IFN-ɣ and IL-13. For this report, we investigated the transcriptome of Chlamydia-specific CD8ɣ13 T cells, comparing them to Chlamydia-specific multifunctional Tc1 clones using gene expression micro array analysis. The molecular study revealed that CD8ɣ13 polarization included IL-5 in addition to IFN-γ and IL-13. Adoptive transfer studies were performed with Tc1 clone and CD8ɣ13 T cell clones to determine whether either influenced bacterial clearance or immunopathology during Chlamydia muridarum (Cm) genital tract infections. To our surprise, an adoptively transferred CD8ɣ13 T cell clone was remarkably proficient at preventing chlamydia immunopathology while the multifunctional Tc1 clone did not enhance clearance or significantly protect from immunopathology. Mapping studies with MHC class I- and class II-deficient splenocytes showed our previously published Chlamydia-specific CD8 T cell clones are MHC class II-restricted. MHC class II-restricted CD8 T cells may play important roles in protection from intracellular pathogens that limit class I antigen presentation or deplete the CD4 T cell compartment.