IGHG3 and infection: In addition, antibody isotype observed in infected and untreated control groups was IgM, whereas immunization induced IgM, IgA, IgG1, and IgG2a antibodies; immunization and infection induced IgM, IgA, IgG1, IgG2a, IgG2b, and IgG3 antibodies (Table 1).