Use of radioimmunoassay for the detection of circulating antistreptococcal antibody in patients with glomerulonephritis

A method of radioimmunologic quantitation of antibodies to streptococcal antigen separated from the cell wall extract of group A type T12 strain has been developed. The extracted and purified antigen was labelled with 125I by the chloramine T method, the specific activity reaching 35 μCi/ug. The radioactive antigen and the tested serum were incubated, then bound and free antigens were separated by precipitation with diethyl dioxide and the radioactivity was counted in the pellet. The quantity of antibodies was determined in different renal diseases and tonsillitis. (L.E.)