The ELY-1 locus controls a di-allelic alloantigenic system on equine lymphocytes.

The ELY-1 locus controls the expression of a polymorphic cell surface antigen of equine lymphocytes which was detected using antibodies generated by alloimmunization with peripheral blood lymphocytes. The ELY-1 antigens were not detected on erythrocytes or platelets by absorption experiments. The two alleles, which have been designated ELY-1.1 and ELY-1.2, are expressed codominantly and appear to constitute a closed system at the population level. In family studies, the ELY-1 antigens segregated as products of an autosomal locus not linked to the major histocompatibility complex (MHC) of the horse. In the complement mediated lymphocyte microcytotoxicity test, antisera to the ELY-1 antigens selectively killed peripheral blood lymphocytes which did not express surface immunoglobulin. The ELY-1 antigens may be useful markers for equine T cells when assayed in this fashion. Three alloantisera were used in immune precipitation of iodinated and solubilized cell surface proteins from peripheral blood lymphocytes. Electrophoresis of the precipitates in sodium dodecyl sulphate (SDS)-polyacrylamide gels demonstrated strong bands in the Mr 180-190K range that were shared in the three different preparations. These results suggest that the ELY-1 allospecificities are expressed on an equine equivalent of the murine T200 molecule.