EQUINE LEUCOCYTE ANTIGEN SYSTEM: III. NON‐MHC LINKED ALLOANTIGENIC SYSTEM IN HORSES

Abstract

A new, non-MHC [major histocompatibility complex] linked alloantigenic membrane antigen on the equine lymphocytes is described. This antigen was characterized with alloantisera in the 2-stage microcytotoxicity test and designated as ELy-1 antigen. The frequency of ELy-1 antigen positive animals in various populations is .apprx. 50%. ELy-1 shows an autosomal, dominant inheritance. Since an allelic antigen (s) could not be demonstrated in family studies, it is assumed that only 2 alleles ELy-1+ and ELy- exist. The ELy-1 antigen in positive animals is expressed on both T and B lymphocytes but it is not present on erythrocytes and thrombocytes. The incidence of ELy-1 antigen positive animals is significantly higher in horse groups suffering from chronic bronchitis or from laminitis, compared to clinically healthy controls.