Two distinct murine differentiation antigens determined by genes linked to the Ly-6 locus

Two separate monoclonal antibodies, 34-11-3S and 34-2-11S, produced by the fusion of C3H anti-BDF1 sensitized spleen cells to the SP2/0 myeloma variant cell line, were found to detect alloantigens on subpopulations of murine lymphocytes. Analysis of the strain specificities of these antibodies showed that both detected antigens determined by genes closely linked to the Ly-6 locus. However, analysis of the tissue distributions of antigen-bearing cells indicated that the 2 antibodies reacted with distinct antigens, only 1 of which was similar in distribution to the classically described Ly-6.2 antigen. Functional studies performed using cells treated with antibody plus C showed that these 2 antibodies defined lymphocyte subpopulations that are different from each other and from those defined by several other reported Ly-6-related antibodies. The data suggest that the Ly-6 locus consists either of multiple tightly linked genes exhibiting marked linkage disequilibrium or of a single gene, the protein product of which is subject to post-translational modifications during cell differentiation leading to the expression of new determinants.