GENETIC-CONTROL OF THE IMMUNE-RESPONSE TO STAPHYLOCOCCAL NUCLEASE .9. RECOMBINATION BETWEEN GENES DETERMINING BALB-C ANTI-NUCLEASE IDIOTYPES AND THE HEAVY-CHAIN ALLOTYPE LOCUS

Abstract

The genetic linkage relationship of 2 antinuclease idiotypes produced by the BALB/c strain was investigated in the backcross (BALB/c .times. CB.20) .times. CB.20. These 2 idiotypes were detected by Lewis rat anti-idiotype antisera prepared against affinity-purified A/J and SJL antinuclease antibodies, termed the A/J and SJL idiotypes, respectively. Both idiotypes were linked to the IgCHa (immunoglobulin H chain allotype) locus. There was a high frequency of recombination observed between both markers and the IgCHa locus, with 8 of 83 backcross animals recombinant for the A/J idiotype and 5 of 83 recombinant for the SJL idiotype. All such recombinant animals were IgCHb/b homozygotes that had gained 1 or both idiotypes. A genetic map of VH [IgCHa variable region] region genes in the BALB/c strain in which genes determining the SJL idiotype are closer to the IgCHa allotype locus than are genes determining the A/J idiotype is supported. This high frequency of recombination may indicate that the chromosome segment containing VH region genes is very large or that it has structural features that promote recombination.