CD40LG and infection: Analysis of virus-specific serum antibody titers at 15, 30 and 60 dpi showed that although titers of virus-specific IgM were comparable in young and aged mice early after infection (days 15 and 30), virus-specific IgM titers were increased in aged mice at 60 dpi (Figure 11A), consistent with an age-associated deficiency in the generation of class-switched antibodies at all timepoints examined (Figure 11B).