IGHG3 and infection: Upon infection with LCMV Cl13 or VSV as above and simultaneous immunization with a T-independent Type 2 (TI-2) antigen, NP-FICOLL, NP-specific IgG3 (Figure 1C), and IgM (Figure 1D) responses were similar in all groups although a trend toward weaker IgM responses in the LCMV-infected group was observed at latter time points.