Genetics of the Idiotype of Strain AKR Antibodies to Group A Streptococcal Carbohydrate; further Evidence for a Low Degree of Homology in the VH Chromosomal Region

A new V_Hgene is described which governs the expression of idiotypes associated with the antibody response of strain AKR mice to Group A streptococcal carbohydrate (A-CHO). This V_H gene, termed ACH^d, is identified using guinea pig antisera to a pool of strain AKR antibodies to A-CHO. The genetic polymorphism is revealed by quantitative differences in idiotype expression between different inbred strains. In recombinant inbred strains linkage to the Ig-l^d allotype allele of strain AKR is demonstrated. In a putative recombinant strain it appears that ACH^d maps at a locus different from that of A5A⁺, another V_H gene controlling idiotypes of anti-A-CHO antibodies. This represents a further example of pseudoallelism between related Vh genes and lack of homology in the V_H chromosomal region. Expression of the ACH^d gene was independent of the Ly-2,3 locus which is associated with kappa chain variants.