Project description:CD4 T cells promote innate and adaptive immune responses, but how vaccine-elicited CD4 T cells contribute to immune protection remains unclear. Here we evaluated whether induction of virus-specific CD4 T cells by vaccination would protect mice against infection with chronic lymphocytic choriomeningitis virus (LCMV). Immunization with vaccines that selectively induced CD4 T cell responses resulted in catastrophic inflammation and mortality following challenge with a persistent form of LCMV. Immunopathology required antigen-specific CD4 T cells and was associated with a cytokine storm, generalized inflammation, and multi-organ system failure. Virus-specific CD8 T cells or antibodies abrogated the pathology. These data demonstrate that vaccine-elicited CD4 T cells in the absence of effective antiviral immune responses can trigger lethal immunopathology. Splenic GP66-specific CD4 T cells from mice immunized with either a LMwt vaccine (sham) or LMgp61 vaccine (CD4 vaccine) were purified by FACS on day 8 post-infection with LCMV clone 13
Project description:CD4 T cells promote innate and adaptive immune responses, but how vaccine-elicited CD4 T cells contribute to immune protection remains unclear. Here we evaluated whether induction of virus-specific CD4 T cells by vaccination would protect mice against infection with chronic lymphocytic choriomeningitis virus (LCMV). Immunization with vaccines that selectively induced CD4 T cell responses resulted in catastrophic inflammation and mortality following challenge with a persistent form of LCMV. Immunopathology required antigen-specific CD4 T cells and was associated with a cytokine storm, generalized inflammation, and multi-organ system failure. Virus-specific CD8 T cells or antibodies abrogated the pathology. These data demonstrate that vaccine-elicited CD4 T cells in the absence of effective antiviral immune responses can trigger lethal immunopathology.
Project description:NK cells may provide a “rheostat” function and have been shown to reduce the magnitude of antigen-specific T cell responses following infection. It remains unknown whether NK cells similarly modulate vaccine-elicited T cell responses following viral challenge. We used the LCMV clone 13 infection model to address whether NK cells regulate T cell responses in Adenovirus vector vaccinated mice following challenge. As expected, NK cell depletion in unvaccinated mice resulted in increased virus-specific CD4+ and CD8+ T cell responses and immunopathology following LCMV challenge. In contrast, NK cell depletion had minimal to no impact on antigen-specific T cell responses in mice that were vaccinated with an Ad5-GP vector prior to LCMV challenge. Moreover, NK cell depletion in vaccinated mice prior to challenge did not result in immunopathology and did not compromise protective efficacy. These data suggest that Adenovirus vaccine-elicited T cells may be less sensitive to NK cell-rheostat regulation than are T cells primed by LCMV infection.
Project description:CD4 and CD8 T cells display functional defects during chronic infection such as loss of certain cytokines. Recent studies have suggested that CD4 T cells may actually gain other functions, however. Here, we analyzed gene expression profiles from LCMV-specific CD4 and CD8 T cells throughout the response to either acute LCMV or chronic LCMV infection. This alllowed us to identify CD4-specific changes during chronic infection compared to acute infection but also revealed shared core regulators between CD4 and CD8 T cells. LCMV-specific CD4 and CD8 T cells were isolated 6, 8, 15 and 30 days post infection with LCMV Armstrong or LCMV clone 13. Naïve CD4 and CD8 T cells were also isolated from naïve mice as comparisons. Four replicates of each sample were hybridized. The only exception is LCMV-specific CD4 T cells isolated 6 days post infection with LCMV-Arm where only three replicates were hybridized.
Project description:CD4 and CD8 T cells display functional defects during chronic infection such as loss of certain cytokines. Recent studies have suggested that CD4 T cells may actually gain other functions, however. Here, we analyzed gene expression profiles from LCMV-specific CD4 and CD8 T cells throughout the response to either acute LCMV or chronic LCMV infection. This alllowed us to identify CD4-specific changes during chronic infection compared to acute infection but also revealed shared core regulators between CD4 and CD8 T cells.
Project description:CD4+ T cells play a critical role in sustaining the effector function of CD8+ T cells during chronic viral infection. When CD4+ T cell “help” is absent, following transient CD4+ T cell depletion, CD8+ T cells enter a dysfunctional state, losing their capacity for viral control. Here, we applied scRNA-seq to determine the CD4+ T cell subsets that repopulate following transient CD4+ T cell depletion, during LCMV Clone 13 infection.
Project description:In this study, we determined the signature of CD4+Foxp3- effector T cells and CD4+Foxp3+ Treg cells in naive animals and following LCMV WE infection. In addition, transcriptional signatures were determined in CXCR3+ CD4+Foxp3+ Treg cells arising in Th1 settings following LCMV infection.
Project description:Following infection with LCMV, CD4+ SMARTA TCR transgenic cells (specific for the gp61-80 epitope of the LCMV glycoprotein) rapidly expand, become effector cells, and go on to form a long-lived memory population. Following infection with a recombinant Listeria monocytogenes expressing the LCMV epitope gp61-80, SMARTA cells also expand but display defective effector differentiation and fail to form memory. In an attempt to understand the signals required for CD4 T cell memory differentiation, we compared gene expression by SMARTA cells at the peak of the primary response following either Lm-gp61 or LCMV infection. Keywords: response to LCMV or Lm-gp61 infection
Project description:TFH cells play an important role in chronic viral infection by helping B cells produce antibodies. Recent studies have identified a novel CD4+ T cell progenitor population in chronic LCMV infection that sustains the differentiation of TFH and other effector CD4+ T cells. However, the details of this differentiation process remain unclear. Here, we report an unprecedented dual role for Themis in regulating the differentiation of CD4+ T cell progenitors into TFH cells during chronic LCMV infection. Themis expression is strongly upregulated in TFH cells at early stages of infection, and as expected, Themis promotes TFH cell differentiation at this stage. However, unexpectedly, at the late stages of chronic LCMV infection, Themis-deficient CD4+ T cells favored TFH cell differentiation and helped control the virus by enhancing GC responses and antibody production, suggesting that Themis inhibits TFH cell differentiation at this stage. In the late stage we found that Themis inhibits the differentiation of CD4+ T cell progenitors into TFH cells through transcriptional regulation.
Project description:Understanding the response of memory CD8 T cells to persistent antigen re-stimulation and the role of CD4 T cell help is critical to the design of successful vaccines for chronic diseases. However, studies comparing the protective abilities and qualities of memory and naïve cells have been mostly performed in acute infections, and little is known about their roles during chronic infections. Herein, we show that memory cells dominate over naïve cells and are protective when present in large enough numbers to quickly reduce infection. In contrast, when infection is not rapidly reduced, memory cells are quickly lost, unlike naïve cells. This loss of memory cells is due to (i) an early block in cell proliferation, (ii) selective regulation by the inhibitory receptor 2B4, and (iii) increased reliance on CD4 T cell help. These findings have important implications towards the design of T cell vaccines against chronic infections and tumors. 16 samples are analyzed: 3 replicates of secondary effector CD8 P14 T cells at day 8 post-acute lymphocytic choriomeningitis virus (LCMV) infection; 4 replicates of secondary effector CD8 P14 T cells at day 8 post-chronic LCMV infection; 4 replicates of primary effector CD8 P14 T cells at day 8 post-acute LCMV infection; and 5 replicates of primary effector CD8 P14 T cells at day 8 post-chronic LCMV infection.