Abstract

 Salt-extractable antigen (SEA) of B. abortus S99 was used in indirect ELISA (i-ELISA) for detection of anti-Brucella antibodies in human and cattle sera. By using Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the SEA contained 5 bands of proteins with molecular weight of 54.000 -116.000 Dalton. Results indicated that the sero prevalence of 96 human sera that clinically suspected with brucellosis, the seroprevalence were 77.1% using rose-Bengal test (RBT) and 94.8% using i-ELISA. More over the result also showed that sero prevalence of 104 cattle sera that clinically suspected with brucellosis the seroprevalence were 79.9% using RBT and 96.2% using i-ELISA. This study concluded that the specificity of the i-ELISA with (SEA) antigen was 100% and the sensitivity was about 95-96%, this indicated to the specified proteins antigen that increased the specificity of the test, also overcome the problem associated with cross-reactivity of antibodies due to in infection with bacteria known to induce immunological cross-reactions with Brucella spp.