CD8A and infection: In both recipient groups, comparable frequencies and numbers of influenza nucleoprotein (NP)-specific CD8+ T cells were detected in the spleens following infection with influenza virus ×31 (Figure 5C, D), suggesting that CD8+ T cells that arose from the FV-infected thymic transplant were bona fide mature T lymphocytes with the intact capability to respond to an FV-unrelated antigen.