Expression of a cross reactive idiotype on the IgG2c subclass of rat anti-streptococcal carbohydrate antibody

Allotypic determinants (Igh-3) associated with the IgG2c subclass of rat immunoglobulins

Rat antibodies to group A streptococcal carbohydrate are primarily of the IgM and IgG isotypes. Hyperimmunization often results in antibodies of a restricted molecular heterogeneity of the IgG2c isotype. An allotypic marker, designated Igh-3a, was detected on the heavy chains of the IgG2c isotype from Copenhagen rats. Igh-3b was detected on the heavy chains of IgG2c from SHR rats. A strain distribution of the Igh-3 determinants as well as inheritance patterns for their expression are presented.

Analysis of a major rat idiotype associated with Anti-GAT antibodies

An anti-idiotypic antiserum was raised in a rabbit against a pool of purified F.344 rat anti-GAT antibodies. GAT-13, the idiotype defined by this serum, is present in all F.344 anti-GAT sera from primary and secondary anti-GAT responses. Anti-GAT sera of 13 inbred rat strains, with different RT1 haplotypes and with different heavy- and light-chain allotypes, all express idiotypic determinants cross-reacting with GAT-13. Thus, like in mice anti-GAT antibodies from rats express public idiotypic determinants. The anti-idiotypic serum also recognizes a highly conserved idiotypic specificity present on mouse and guinea-pig anti-GAT antibodies. The mouse, rat and guinea-pig express a similar highly conserved idiotypic specificity after immunization with GAT. All anti-GAT antibodies from the mouse and guinea-pig bear this idiotypic specificity. These results confirm the existence in the anti-GAT response of interspecies cross-reactive idiotypic determinants.

Inheritance patterns of idiotype expression: maternal-fetal immune regulatory networks

The production of Id-1, a cross-reactive idiotype associated with rat anti-group. A streptococcal carbohydrate antibodies, by 11 strains of rats indicates that genes coding for Id-1 are in the germline. Its expression, however, follows a complex inheritance pattern. It was our intent in these studies to determine if immune responsiveness of streptococcus (GASV) immunized females could alter Id-1 expression of GASV-immunized progeny, and, in turn, introduce complications in Id-1 inheritance patterns. - We observed that Id-1-specific immune reactivity of GASV-immunized females could induce significant alterations in Id-1 production by progeny. The relationship between maternal and progeny Id-1 was complex, reflecting the complexity of autologous regulation of Id-1 production, and could be the opposite of what one would predict based upon parental transfer of Id-1 regulatory genes. The nongenetic nature of the maternal regulatory influence was confirmed by foster-mother studies. - We conclude that antigen-induced maternal immune responsiveness can exert a permanent regulatory influence on idiotype expression by progeny and consequently introduce error in to the interpretations of idiotype inheritance patterns. The recognition of this maternal regulatory influence also lends further support to Jerne's hypothesis that idiotype-specific immune networks play a significant role in the regulation of immune responsiveness in vivo.

Subclass restriction of murine antibodies. III. Antigens that stimulate IgG3 in mice stimulate IgG2c in rats

The IgG subclass distribution of rat antibodies to 13 different antigens was measured. Antibodies to protein and hapten-protein conjugates were predominantly IgG2a. Antigens labeled thymus-independent type 1, based upon responses in mice, stimulated both IgG2b and IgG2c antibodies, but little IgG2a. Polysaccharide and hapten-polysaccharide antigens (thymus-independent type 2) as well as phosphocholine-keyhole limpet hemocyanin, stimulated predominantly IgG2c antibodies. A division of antigens into essentially the same categories has been made on the basis of subclass restriction in mice. Antigens that stimulate IgG2c in rats stimulate IgG3 in mice. Thus, by comparing subclass preference with a variety of antigens, functional analogues among subclasses in different species can be identified.