Characterization of an immune response gene in mice controlling IgE and IgG antibody responses to ragweed pollen extract and its 2,4‐dinitrophenylated derivative

The strain distribution of IgE and IgG antibody responses to ragweed extract (RE) and its dinitrophenylated derivative (DNPRE) characterize a new immune response gene, Ir ‐ RE . Responder strains show higher primary and secondary levels of both antibody classes than nonresponders after immunization with these antigens in aluminium hydroxide gel, the differences being most marked at low doses, but present over a wide dose range (10 to 500 μg/mouse). High responses are associated with H ‐2 a, d, h, k, m, n and p types; low responses with H ‐2 b, f, i, j and u . The Ir ‐ RE gene has been mapped to the H ‐2 region by the use of congenic resistant strains, and to the H2K ‐ Ir ‐ 1 region with H ‐2 recombinants. The high response allele is dominant and appears, by its regulation of anti‐hapten responses in the DNP‐RE hapten‐carrier system, to act at the cellular level of thymus‐derived lymphocytes. T cells possessing this gene control responses of IgG and IgE·B lymphocytes in a parallel fashion.