Unequal Association of Mouse Allotypes with Antibodies of Different Specificities

Summary The experiments were concerned with whether in F1 heterozygous mice the two parental allotypes are expressed in constant proportions among antibody-producing cells or whether their proportions vary from mouse to mouse. Poly-L-alanine and poly-d-alanine were used as non-crossreacting haptenes. Antibody production by individual spleen cells was recorded in a plaque assay procedure for which the poly-alanine haptenes were linked to rabbit antibodies (IgG) against sheep red blood cells, which in turn were attached to sheep red blood cells. The allotypes of antibodies produced by the individual spleen cells were determined by the facilitation reaction employing reciprocal allotype antisera prepared in the parental mouse strains. A wide fluctuation was found from mouse to mouse in the proportions of cells producing antibodies of the two parental allotypes, especially when the “weaker” haptene, poly-L-alanine, was used as the antigenic determinant. The distribution of the allotype ratios as recorded for poly-L-alanine was heterogeneous in the group of mice studied. In mice injected with both poly-D- and poly-L-alanine, the allotype ratios recorded with poly-L-alanine were not correlated with the allotype ratios recorded with poly-D-alanine. The results are interpreted to mean that the cellular determination to produce antibodies of a given specificity, and the decision about which of two allelic chromosome regions will be active, are associated and are transmitted together in cell lines or clones.