The Complement Fixation Reaction for Measurement of Immunogenic Antigens in Formaldehyde-Inactivated Poliomyelitis Vaccine

Abstract

Summary A method for measuring complement fixation (CF) antigens in formaldehyde-inactivated poliomyelitis vaccine has been described in detail. The antisera used were absorbed with heated polioviruses to make the test specific for the types I, II and III D-antigens. A high degree of type specificity has been demonstrated and statistical analyses have indicated that replicate assays are reproducible within narrow limits. The ability of trace amounts of anticomplementary substances to produce significant shifts in the end point of the titration has been clearly demonstrated. The levels of these substances can be reduced by dialysis against Carbowax and by ultracentrifugation procedures which also effectively concentrate the D-antigen. A variety of experiments were carried out, to investigate correlation between CF measurements of the D-antigen and antigenic response in chicks. These included the yield of antigen following concentration and purification of vaccines, loss of antigen during formaldehydeinactivation and loss on long term storage at refrigerator temperature. In the latter there was evidence that the loss of potency was somewhat greater when measured by chick tests than by CF but the two methods showed an encouraging degree of correlation. It is suggested that CF testing with anti-D sera can provide useful data for accurate standardization of poliomyelitis vaccines.