ABSTRACT
The effect of beta-propiolactone (BPL) on the infectivity and haemagglutinating properties of BK virus was studied. No virus multiplication was observed when Vero cell cultures were inoculated with virus treated with 0.1 per cent or higher concentration of BPL. On the other hand, treatment of BK virus with 0.1 per cent or lower concentration of BPL had no apparent effect on viral haemagglutinin. BPL at a concentration of 0.1 per cent could therefore be used to prepare BK virus haemagglutinin which contains little or no infectious virus. Inactivated haemagglutinin seems to be somewhat labile against freezing and thawing, but storage at 4 degrees C had no effect on it. Identical haemagglutination inhibiting antibody titres were obtained when human sera were tested with standard haemagglutinin or with haemagglutinin inactivated with BPL.
