Suppression of Synthesis of Allotypically Defined Immunoglobulins and Compensation by another Sub-class of Immunoglobulin

Abstract

AMONG the light chains of the rabbit immunoglobulin molecules four allotypically determined molecular species can be distinguished : A4, A5, A61 and A92. These specificities are determined by allelic genes at the Ab allotypic locus1,2. Thus a rabbit homozygous at this locus synthesizes only one of these specificities, but a heterozygous rabbit synthesizes two. The phenotypic expression of the synthesizing capacity of heterozygotes can be altered by administration of anti-allotype antibody; synthesis of immunoglobulins of the paternal type can be inhibited (“suppressed”) either by uterine transfer3–7 of allotype antibody from the mothers immunized against the allotypic specificity of the prospective father8 or by injecting the young rabbits with allotype antiserum during the first few days of life9–11. When a heterozygous rabbit is exposed to anti-allotype serum the resulting suppression of one allotypic specificity is compensated by increased synthesis of the product of the second allele; thus the total concentration of IgG is not affected and is similar to that of the normal rabbits9,11.