Estimation of Tetanus Toxoid by Different Methods including Haemagglutination Inhibition

摘要

Comparative quantitative estimations of tetanus toxoid by different methods have been made. The in vivo total combining power test is considered likely to give a true assessment of the combination of toxoid with antitoxin since it is based on the biological action of toxin. The haemagglutination inhibition test has been found to give good agreement with the in vivo test and it is cheap, sensitive and readily repeatable. Since the haemagglutination inhibition test can be performed with toxin or toxoid by the same method, it is possible to relate the quantitative estimation of toxoid to the L+ dose of a routine test toxin, and thus to a standard antitoxin, which is convenient.Considerable discrepancies have been found between results in the flocculation test and the in vivo total combining power test, particularly with toxoids denatured by heat and phenol, or modified by formalin. Discrepanicies between the flocculation and in vivo tests with many preparations have been related to the concentration of residual free formalin.