Rabbit bone marrow-derived (B)2 lymphocytes have immunoglobulin (Ig) on their surface (1–12). Oddly, various workers have reported for the last decade that in lymphocyte populations, the cells bearing the genetic markers of the κ-light chain (b locus allotypes) outnumbered 2 to 4 times the cells bearing the a locus allotypes of the heavy chain (1–5, 10). By using a more sensitive immunocytoadhesion method, we found in rabbit blood that the cells bearing heavy chains numerically equaled the cells bearing light chains. We also directly demonstrated that most B lymphocytes bore the light chains together with the heavy chains.
We have recently (13–15) shown that erythrocytes artificially coated with an antibody (Ab-E) agglutinated and lysed, when reacted with the complementary soluble antigen. When the antigen was cell bound, Ab-E adhered to the cell membrane (rosetting of antigen-bearing cells with Ab-E). Thus, rabbit lymphocytes rosetted with Ab-E specific for the b allotypes.