CD8A and infection: We next modeled secondary homotypic and heterotypic DENV infections in HLA transgenic Ifnar1−/− mice and observed that CD8+ T cell responses were broad (targeting both structural and NS proteins) following primary and homotypic secondary infection, whereas CD8+ T cell responses following heterotypic secondary infection focused toward the conserved NS proteins (28), as observed in humans with natural DENV reinfections (19, 21, 30).