Interaction of non-specific inhibitor and rabies virus haemagglutinim

In order to elucidate the properties of an inhibitor of rabies virus haemagglutinin in normal animal sera, experiments were made with the HEP Flury strain and calf serum which contains the inhibitor. The results of physico-chemical treatment, gel-filtration and density analysis suggested lipoprotein involvement. When inhibitor and haemagglutinin were mixed, the separate activities could be recovered from the mixture by centrifuging on a sucrose density gradient. By contrast, neither haemagglutinin nor inhibitor could be recovered by this treamtnet when the inhibitor was added at the start of virus growth. The binding of inhibitor with rabies virus during virus growth seems irreversible and different from the binding of inhibitor with pre-formed rabies haemagglutinin.