Correlation of Infectivity and Hemagglutinins of Reoviruses ∗

Summary

All three reovirus prototypes were grown in MKTC; the infected cultures were maintained at 37° for up to 42 days. During this time period infectivity and HA of the reoviruses were periodically determined. The infectivity of all three types steadily declined to less than 1% of the maximal titer after 30 days. The HA of types 1 and 2 remained unchanged over a period of 28 days; type 3 HA increased over this time interval and titers of 128 HA units were reached. The infectious and noninfectious HA moiety of the periodic harvests were separated in a CsCl gradient. The changes (type 3) or stability of HA (types 1 and 2) were equally reflected in both moieties; no accumulation of noninfectious HA was found which would account for the persistence of HA and concurrent loss of infectivity.