Detection of group B streptococcal antibodies in human sera by radioimmunoassay: concentrations of type-specific antibodies in sera of adults and infants infected with group B streptococci.
Current interest in determining the possible protective role of antibodies against group B streptococcal disease prompted this study of the feasibility of using a radioimmunoassay to measure type-specific immunity in humans. The radioimmunoassay was standardized as a quantitative test for antibodies against the carbohydrate (CHO) antigens of all five group B types. The data showed that the CHO antigens extracted by a cold trichloroacetic acid-sonification method measure more antibodies than do the corresponding CHO antigens extracted by hot hydrochloric acid; that the Ia CHOs extracted from two different types, Ia and Ic, measure the same quantity of Ia antibodies; and that human sera contain antibodies reactive with all five type-specific CHOs. No evidence of "protective" antibody was found in the serum samples studied, although there was evidence of and antibody response in adults to prolonged colonization by group B streptococci. The wide ranges of antibody concentration in a serum bank collection, the broad reactivity of all human sera tested, and the mixed populations of antibodies in human sera that react with different determinants on the same type-specific CHO antigen (type III) indicate that further studies must be done to better define normal and susceptible populations and to determine antigenic components important in protection.
D000328:Adult; D000907:Antibodies, Bacterial / Q000032:analysis*; D000918:Antibody Specificity; D000942:Antigens, Bacterial; D005260:Female; D006801:Humans; D007109:Immunity; D007223:Infant; D008297:Male; D008581:Meningitis / Q000276:immunology; D011863:Radioimmunoassay / Q000592:standards; D018805:Sepsis / Q000276:immunology; D013290:Streptococcal Infections / Q000276:immunology*; D013292:Streptococcus agalactiae / Q000276:immunology*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial