CD8+ T cells express a T-helper 1-like phenotype after burn injury

Background. Previous studies suggest that CD8(+) T cells are immunosuppressive after burn injury, but recent reports indicate that CD8(+) T cells have several functions similar to CD4(+) T cells, including the secretion of cytokines. This study uses HY male antigen in transgenic HY female mice to determine the antigen-specific response of activated CD8(+) T cells after burn injury. Methods. HY TCR transgenic female mice underwent burn or sham injury. Seventy-two hours after the burn, splenocytes were stimulated with 20 mu mol/L HY peptide for 16, 48, and 64 hours; cellular Proliferation, intracellular interferon-gamma and interleukin-2, and apoptosis were measured. Results. Burn injury significantly impaired proliferation to HY antigen (P less than or equal to .05). Activated CD8(+) T cells from burned mice showed increased intracellular interferon-gamma and interleukin-2 16 hours after stimulation compared with sham (P less than or equal to .05) and at no time was less than control mice. The percent of CD8(+) T cells decreased with the time of stimulation but was not due to apoptosis by Annexin V staining. Conclusions. Activated CD8(+) T cells express a T-H1-like phenotype after burn injury. This provides evidence that CD8(+) T cells are not simply suppressive and that is consistent with data that CD4(+) T cells are primed for a T-H1 response after burn injury.