Evaluation of the effectiveness of receptor destroying enzyme preparations.

A procedure has been developed for testing receptor destroying enzyme (RDE) preparations used to remove nonspecific inhibitors before carrying out haemagglutination inhibition tests with influenza virus. Four criteria should be taken into account: (1) titre of RDE, usually used to indicate the activity of the preparation; (2) neuraminidase activity of the preparation, determined biochemically, which partially corresponds to the RDE titre; (3) direct demonstration of the complete removal of nonspecific inhibitors; and (4) determination that the RDE preparation does not affect specific antibody.