CD40LG and infection: We found that both types of immunizations induced a robust anti-ViPS IgM response that peaked at 7 days post-infection (Fig. 4IA,IIA) as in immunocompetent C57BL/6J mice35 and the serum obtained from the CC003/Unc mice at this time point was capable of killing S. Typhi in vitro in a complement-dependent serum bactericidal assay (Fig. 4IC,IIC).