Methods and procedures for use of complement-fixation technique in type- and strain-specific diagnosis of influenza.

It is now well established that there are two kinds of complement-fixing antigens of influenza virus: the soluble, type-specific, antigens, found mainly in infected tissue but also within the virus particle; and the virus, strain-specific, antigens, closely linked with the haemagglutinating component. For true results in complement-fixation testing in influenza, antigens or antisera of the one kind must be free of the other kind. This paper describes in detail the preparation of reagents for such testing and a variety of basic aspects of test procedures.