'Allelic' forms of immunoglobulin V genes in different strains of mice.

A VH gene (Ox1) has a major role in the early antibody response of several mouse strains to hapten phenyloxazolone (phOx). Antibodies that are coded by this gene are positive for idiotype 495. Idiotype-positive monoclonal antibodies originating from the early primary response of nine strains were partially sequenced (mRNA). All 21 antibodies were coded by this gene, most of them also by one VL gene, VKOx1(H3). Very few somatic mutations were found, and the germ-line sequence of the two genes in several strains can be predicted. Four 'alleles' of the VHOx1 gene have 99-99.7% sequence homology to each other. One allele was found in Igh allotype j strains CBA and C3H, another in allotype c strains DBA/2 and RF, the third in allotype f strain CE and the fourth in BALB/c, 129, A/J and RIII mice (allotypes a, e or g). The VKOx1(H3) gene has the same sequence in eight strains. RF mice do not use this gene for the anti-phOx response. Our data suggest that antibody responses are inherited to a considerable extent and that immunoglobulin V genes are as stable as other genes in evolution.