Coxsackievirus B3 elicits a sex-specific CD8+ T cell response which protects female mice

Coxsackievirus infection induces direct pancreatic β cell killing but poor antiviral CD8+ T cell responses

Coxsackievirus B (CVB) infection of pancreatic β cells is associated with β cell autoimmunity and type 1 diabetes. We investigated how CVB affects human β cells and anti-CVB T cell responses. β cells were efficiently infected by CVB in vitro, down-regulated human leukocyte antigen (HLA) class I, and presented few, selected HLA-bound viral peptides. Circulating CD8+ T cells from CVB-seropositive individuals recognized a fraction of these peptides; only another subfraction was targeted by effector/memory T cells that expressed exhaustion marker PD-1. T cells recognizing a CVB epitope cross-reacted with β cell antigen GAD. Infected β cells, which formed filopodia to propagate infection, were more efficiently killed by CVB than by CVB-reactive T cells. Our in vitro and ex vivo data highlight limited CD8+ T cell responses to CVB, supporting the rationale for CVB vaccination trials for type 1 diabetes prevention. CD8+ T cells recognizing structural and nonstructural CVB epitopes provide biomarkers to differentially follow response to infection and vaccination.

A viral-specific CD4+ T cell response protects female mice from Coxsackievirus B3 infection

Background

Biological sex plays an integral role in the immune response to various pathogens. The underlying basis for these sex differences is still not well defined. Here, we show that Coxsackievirus B3 (CVB3) induces a viral-specific CD4+ T cell response that can protect female mice from mortality.

Methods

We inoculated C57BL/6 Ifnar-/- mice with CVB3. We investigated the T cell response in the spleen and mesenteric lymph nodes in male and female mice following infection.

Results

We found that CVB3 can induce expansion of CD62Llo CD4+ T cells in the mesenteric lymph node and spleen of female but not male mice as early as 5 days post-inoculation, indicative of activation. Using a recombinant CVB3 virus expressing a model CD4+ T cell epitope, we found that this response is due to viral antigen and not bystander activation. Finally, the depletion of CD4+ T cells before infection increased mortality in female mice, indicating that CD4+ T cells play a protective role against CVB3 in our model.

Conclusions

Overall, these data demonstrated that CVB3 can induce an early CD4 response in female but not male mice and further emphasize how sex differences in immune responses to pathogens affect disease.

A viral-specific CD4 + T cell response protects female mice from Coxsackievirus B3 infection

Biological sex plays an integral role in the immune response to various pathogens. The underlying basis for these sex differences is still not well defined. Here, we show that Coxsackievirus B3 (CVB3) induces a viral-specific CD4 + T cell response that can protect female mice from mortality. We found that CVB3 can induce expansion of CD62L lo CD4 + T cells in the mesenteric lymph node and spleen of female but not male mice as early as 5 days post-inoculation, indicative of activation. Using a recombinant CVB3 virus expressing a model CD4 + T cell epitope, we found that this response is due to viral antigen and not bystander activation. Finally, the depletion of CD4 + T cells before infection increased mortality in female mice, indicating that CD4 + T cells play a protective role against CVB3 in our model. Overall, these data demonstrated that CVB3 can induce an early CD4 response in female but not male mice and further emphasize how sex differences in immune responses to pathogens affect disease outcomes.