CD4 and infection: Most recently, we uncovered the immune-mechanism of protection involved TLR2-mediated production of IFNγ and IL-17A by γδ T cells resulting in a robust CD4+ or CD8+ T cell response for complete host protection to subsequent WT infection (T.G. Normile, T.H. Chu, B.S. Sheridan, and M. Del Poeta, submitted for publication).