Immune responses to Mycoplasma conjunctivae in alpine ibex, alpine chamois, and domestic sheep in Switzerland

The humoral immune response of three alpine chamois (Rupicapra rupicapra ru picapra), two alpine ibex (Capra ibex ibex) and three domestic sheep natura lly affected with infectious keratoconjunctivitis (IKC), and four ibex and two sheep experimentally infected with Mycoplasma conjunctivae was analysed . In addition, the local immune response to M, conjunctivae was analysed us ing conjunctival washes from chamois and sheep. Immunoblot analysis of sera using whole cell antigens of M. conjunctivae revealed the major immunogeni c proteins which had molecular masses of 175, 83, 68, 60, 50, 42, 36, and 3 3 kDa. Major antigens were found at 83, 68, 60, and 42 kDa in both sera and conjunctival washes from naturally infected animals of all three Caprinae species. In experimentally infected animals, antibodies to the 68 and 60 kD a antigens were dominant. Naturally infected animals showed much stronger i mmune reactions than those experimentally infected, and specific antibodies appeared 2 to 4 wk after experimental infection. To evaluate possible cros s-reactions, whole cell antigen of M. conjunctivae was analysed by immunobl ot against hyperimmune sera of closely related Mycoplasma spp. Antibodies t o the 175, 73, 68, 60, and 33 kDa antigens appeared to be specific to ill. conjunctivae. Cross-reactions mainly with 83, 50, and 42 kDa antigens were detected, in particular with M. ovipneumoniae and M. bovoculi hyperimmune s era, but also with antisera against M. capricolum capricolum and M putrefac iens.