The direct flocculation of influenza virus

The influenza virus flocculation reaction as a method of antigenic typing

The influenza virus serum flocculation previously reported (Belyavin, 1955) opened up a number of lines of investigation. One of obvious importance was extension of the reaction to other viruses belonging to both related and unrelated groups. Indeed, other workers in this laboratory have already achieved the flocculation of poliomyelitis viruses by specific antisera (Smith, Sheffield, Lee & Churcher, 1956) and flocculation of both mumps and Newcastle disease viruses is now reported in this communication. The ease with which the viruses of the mumps-influenza group can be flocculated by homologous rabbit antisera suggested that the technique may be applicable as a method of antigenic analysis. If so, it would have the advantage of being much simpler than the standard haemagglutination inhibition and complement-fixation tests. The exploration of this possibility forms the basis of this paper. A large-scale antigenic survey involving numerous virus strains has not been attempted, greater emphasis being placed on the examination of techniques and their applicability to the end in view. The investigation has also revealed new phenomena peculiar to the direct virus flocculation reaction.