| Abstract: | Six equine lymphocyte alloantigen (ELA) specificities were defined by an international antiserum comparison test and workshop held in 1981. Twelve laboratories from four countries submitted 195 antisera for analysis. The antisera were exchanged among the 12 laboratories and tested in a standard lymphocyte microcytoxicity assay against the isolated lymphocytes at 1009 horses of several breeds. The data was pooled and analysed by a single computer analysis. The calculated χ2 values of all cells with all antisera provided comparisons between antisera. Fifteen antisera clusters were formed by this analysis, but only six of these clusters met the criteria established by the workshop for the identification of ELA antigens. No horses of the cell panel positively reacted with more than two of these six specificities. The consensus of the participants, although not substantiated in this workshop, was that these six clusters of antisera define alleles of a single genetic region, the ELA region, and it is likely that this genetic region is the major histocompatibility complex of the horse. |
