AN ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR EVALUATION OF AN EXPERIMENTAL SALMONELLA-TYPHIMURIUM VACCINE IN 2 BREEDS OF EWES

An enzyme-linked immunosorbent assay (ELISA) for quantitation of antib odies, following immunization with an experimental Salmonella typhimur ium vaccine in two postpartum breeds of ewes, was standardized, Based on analysis of variance, the two breeds of ewes, purebred Awassi and c rossbred Finn x Texel x Awassi (FTA), did not differ in the ELISA-anti body levels following immunization with an experimental formalin inact ivated oil based S. typhimurium vaccine (P > 0.05). However, vaccinati on in both breeds resulted in higher significant antibody level than u nvaccinated ewes. The antibody level quantitated in both breeds increa sed significantly at 2 weeks after the first immunization (P < 0.01), then decreased slightly 3 weeks later, in spite of a booster administr ation at 2 weeks after the first immunization. Seroconversion at 2 wee ks after the first immunization was 66.7% in each breed (P > 0.05); ho wever, it increased to 100% at 3 weeks after the booster in Awassi ewe s, while it was maintained at 66.7% in the FTA ewes. This work implies the ability of the administered vaccine to induce antibody response i n both ewe breeds that could be quantified by the developed ELISA.