When we analyzed proportions of splenic T cells two weeks post infection with L. interrogans (Figures 5 and 6) we found increased populations of CD4+ effector T cells in infected versus uninfected mice in WT, huTLR4 and muTLR4Lps-del which was consistent with our previous observations in C3H-HeJ mice (8, 10). This evidence concerns the gene CD4 and infection.