Biophysical and immunological studies on the differential effect of guanidine hydrochloride on type A and type B influenza viruses.

Guanidine hydrochloride selectively inactivated both the biological activity and the immunogenicity of the haemagglutinin of influenza A/X-7 (HON2). The residual neuraminidase was fully active biologically and immunologically. The reverse was observed with influenza B/ROB; with this virus the haemagglutinin was resistant, and was immunogenic; while the neuraminidase was selectively inactivated, and was not immunogenic.