Sensitivity of Various H Particles of Poliovirus to Alkaline Treatment

Four kinds of H antigenic particles (H particles) of poliovirus were prepared, (1) by mild alkaline treatment of virions (Alkaline‐H), (2) by separation from the virus infected culture (Natural‐H), (3) by ultraviolet irradiation of virions (UV‐H), (4) by heating of virions (Heat‐H). They were examined for sensitivity to an alkaline degradation (pH 10.5 at 40 C). Heat‐H was most stable and no degradation of capsid was observed after the treatment. UV‐H was most unstable, since it was completely disrupted into small components after the treatment. Alkaline‐H and Natural‐H were relatively stable but a minor amount of small component(s) was liberated therefrom by the treatment. These results suggest that the H particles induced by the four procedures are different from each other in the stability of capsid structure. Furthermore, it is suggested that the antigenicity(s) of the small‐size component(s) is different from either N or H antigenicity being ascribable to VP2 polymer.