2,4‐Dinitrophenyl‐lysin B29 ‐bovine insulin was used as immunogen to investigate the carrier function of insulin in the induction of immune response. Experiments with backcross mice suggest that this is controlled by autosomal Ir genes. The response pattern shown by congenic mice demonstrate the linkage of these genes to the H‐2 complex. With a standard dose of 20 μg per mouse, strains with the H‐2 haplotypes d,b,v respond to this carrier. All other strains tested, with the H‐2 haplotypes a,k,u,r,s,q, are nonresponders.
The two Ir genes, Ir‐insulinBov (H‐2d) and Ir‐insulinBov (H‐2b), which are associated with H‐2d and H‐2b respectively, can be distinguished from one another on a functional basis. Only H‐2d mice respond to an appreciable extent when B. pertussis organisms are the adjuvant. With complete Freund's adjuvant, H‐2d and H‐2b mice give high antibody titers, but with low doses of antigen only H‐2d mice respond. In contrast to H‐2d mice, H‐2b mice do not respond to trifluoresceinthiocarbamyl insulin, suggesting that the dimeric insulin might be the immunogenic form in these mice. Furthermore, as has been shown earlier (Nature, 1975. 254: 78.), the A‐chain loop is needed as a carrier determinant only in H‐2b mice.
Experiments with recombinant strains localize Ir‐insulinBov (H‐2b) to the left of Ir‐1B, probably in Ir‐1A.
H‐2k mice are strict nonresponders, even when other proteins such as bovine IgG, methylated bovine serum albumin or rabbit IgG are provided as carriers complexed with insulin. However, if proinsulin is used as the antigen, anti‐insulin antibody can easily be raised in these strains.