Murine lymphocyte alloantigens. I. The Ly-6 locus.

The Ly-6 locus and the Ly-6.2 specificity have been previously described, and we now further define this locus and the allelic specificities, Ly-6.1 and Ly-6.2. Back-cross studies and examination of several recombinant inbred (RI) lines demonstrate that Ly-6 is distinct from other loci determining CMAD, except for ALA-1 and evidence is presented for the identity of Ly-6 and ALA-1. The Ly-6 congenic strain C3H.B6-Ly-6b is described and was used to prepare antisera in combinations congenic for Ly-6. The allelism of the Ly-6.1 and Ly-6.2 specificities was confirmed by the reactivity of these antisera with a segregating F2 generation. Antisera can be prepared between the Ly-6 congenic strains, although the magnitude of the response is under the control of one or more genes in A strain, not linked to H-2 or Ly-4 loci. Absorption analysis using separated T and B lymphocyte populations demonstrate that Ly-6.2 does not have exclusive peripheral T cell representation as originally reported, but is also present on B cells in amounts one-fourth to one-eighth of that found on T cells and is found in greater quantities on T blast cells.