CD40LG and infection: Here, O PA2-C3d and A22-C3d were effectively induced not only the SP-specific antibody titers (via SP ELISA), but also the SP-nonspecific antibody including IgG (an indicator of neutralizing antibody), IgM (the first natural antibody induced during pathogen infection or vaccination) and IgA (the key player in inducing mucosal immunity) levels in MDA(+)/MDA(−) animals (Fig. 6).