[Use of group A-specific polysaccharide antigen conjugated with protein carrier for detection of specific anti-polysaccharide antibodies].

Group-A specific polysaccharide antigen has been obtained by extraction of streptococcal suspension using 4N NaNO2 and glacial acetic acid, conjugated with bovine serum albumin using CNBr. Testing of the preparation with a set of rabbit anti-sera by enzyme immunoassay (EIA) and passive hemagglutination reaction (PHR) revealed its antigenic specificity both in direct experiments and in N-acetyl-D-glucosamine absorption. Forty-seven sera of EIA-studied individuals and 35 sera of PHR-studied ones, all with group-specific polysaccharide antigen, were examined. Immune reactions showed the broad spectrum of antibody titres in the studied sera. Complete correlation of anti-polysaccharide antibodies detected by the two techniques was observed in the sera with high specific antibody titres. A possibility to use the obtained group-A specific polysaccharide antigen to detect anti-polysaccharide antibodies in the sera of streptococcal infection patients is discussed.