Genes associated with the G2m (23) immunoglobulin allotype regulate the IgG subclass responses to Haemophilus influenza type b polysaccharide vaccine

We determined whether genes associated with the G2m(23) allotype, a genetic marker on IgG2 molecules, influence the subclass composition of the antibody response to Hae-mophi/us influenzae type b polysaccharide vaccine. After immunizing 70 white adults, the geometric means (GMs) of the total, IgG, IgG1, and IgG2 antibody concentrations increased ""to-fold over preimmunization concentrations. There was no significant differ-ence in the GMs of the total, IgG, or IgG1 antibody concentrations in postimmunization sera from subjects positive versusthose negative for G2m(23). Adults positive for G2m(23) had a GM IgG2 concentration more than threefold higher than that of negative subjects (P <.001). The antibody responses of 61 Amish adults immunized with type b polysac-charide vaccine were also analyzed. Those adults positive for G2m(23) had a higher GM serum IgG2 response to capsule than did those who were negative (P <.01). These data indicate that genes associated with the G2m(23) locus regulate the IgG subclass composi-tion of the antibody response to H. influenzae type b polysaccharide vaccine. Genes associated with certain immunoglobulin al-lotypes have been shown to affect the magnitude o