AN OVINE LYMPHOCYTE ANTIGEN IS ASSOCIATED WITH REDUCED FECAL EGG COUNTS IN 4-MONTH-OLD LAMBS FOLLOWING NATURAL, PREDOMINANTLY OSTERTAGIA-CIRCUMCINCTA INFECTION

Ten lymphocyte antigens were defined in a flock of Scottish Blackface sheep known to be naturally exposed to infection with Ostertagia circu mcincta. Population and family studies suggested that the 10 antigens were products of class I loci, Antigen G13br was in linkage disequilib rium with allele g2 at the DRB1 locus. The g2 allele has previously be en associated with reduced faecal egg counts in a different crop of la mbs from the same farm, In this study antigen G13br was also associate d with a reduction in faecal egg counts. The results provide partial c onfirmation of the role of the major histocompatibility complex in res istance to natural, predominantly O. circumcincta infection. Copyright (C) 1996 Australian Society for Parasitology.