Single radial complement fixation test using complement film. Assay of the antibody response to strain and type...

A stabilized modification of the single radial complement fixation test in gel (SRCF) was developed for detecting influenza antibodies. The principle of the test is the use of a single-step procedure with the following reagents: (1) Agarose plate containing influenza antigen and antibody coated erythrocytes (EA). (2) Thin plastic film coated with dried complement. By filling the wells cut in the agar with the heat inactivated serum samples and covering the agar surface with the complement film, a zone of unlysed cells surrounded by a haemolytic area appears after overnight incubation for 16-18 h at 4 degrees C and 1-2 h at 37 degrees C. The squares of the zone diameter were measured for estimating the antibody quantity by using CF(S) and virion antigen of influenza virus, and the type-specific antibody was demonstrated by using CF(S) antigen, while the strain-specific antibody was demonstrated by using virion antigen. An excellent correlation was demonstrated for antibody titres between conventional CF and SRCF with CF(S) antigen, on the one hand, and, between conventional HI and SRCF with virion antigen, on the other.(ABSTRACT TRUNCATED AT 250 WORDS)