H-2-Linked Ir Gene Control of Antibody Responses to Insulin

Abstract

The immune response to insulin in the mouse is under MHC-linked Ir gene control (only H-2^d mice respond to pork insulin whereas H-2^b, H-2^d, and H-2^v respond to beef insulin; H-2^{a, q, k, r, s} respond to neither). In addition, species variants of insulin can be used to study the effects of specific amino acid exchanges on the immune response. To evaluate these effects at the cellular level, a new technique has been developed for covalently coupling insulin to SRBC. Two bifunctional reagents (methyl-4-mercaptobutyrimidate and m-maleimidobenzoyl N-hydroxysuccinimide ester) were used to prepare insulin-SRBC for use in a modified Jerne plaque assay. Nonresponder mice failed to make a significant anti-insulin IgM or IgG PFC response over the entire course of a primary response to beef (H-2^k and H-2^q) or pork (H-2^b, H-2^k and H-2^q) insulin. Responder and F₁ (responder × nonresponder) mice make mostly IgG anti-insulin PFC with about 50% being IgG1 and 50% IgG2. Extensive cross-reactivity between beef and pork insulin after immunization with one insulin was found at the antibody-secreting cell level. Control of the response of H-2^b mice to DNP-beef insulin has been mapped previously in either the K or I-A region. The present study maps the control of the H-2^b PFC response to native beef insulin in this same region(s).