Occurrence of caprine leucocyte antigens (CLA) in Creole goats susceptible/resistant to heartwater.

A genetic predisposition to the manifestation of disease symptoms has been demonstrated for heartwater in certain goat lines. In order to clarify a possible involvement of the major histocompatibility complex (MHC) in the pathogenesis of heartwater, over 100 Creole goats have been typed serologically for their CLA class I antigens coded by the caprine MHC. The MHC is a genetic system that influences different immunological processes, i.e. the individual immune response. With our alloantisera we were able to detect 13 different CLA alleles also present in the Swiss breeds, two non-MHC antigens, a new cluster defined by the splitting of two antigens and several specific reaction patterns of single reagents. The allele frequencies of the detected CLA antigens differed for the resistant and susceptible groups examined. Whether the differences represent regional sire effects or indicate pathogen-induced selection pressure remains to be clarified. Additional testing of resistant/susceptible goats originating from common environment as well as of specially crossbred (resistant x susceptible) animals are underway.