Characterization of the IgG antibody response to timothy grass pollen antigens.

The IgG and IgE antibody responses against timothy grass pollen antigen B (AgB) in several mouse strains were determined. Considerable variability in both responses was demonstrated, and (CBA/J X C57BL/6)F1 mice were selected for use in subsequent experiments. Anti-idiotypic-antibody-induced T suppressor cells almost completely suppressed AgB-specific IgE, but the IgG response was not altered. Further studies with photooxidized AgB (Ox-AgB) indicated that the IgG response was directed against an antigenic determinant expressed on both native antigen and Ox-AgB. Our data indicates that AgB possesses two distinct antigenic determinants, one that induces an IgE response, and one that induces an IgG response.