ENHANCEMENT OF AQUAREOVIRUS INFECTIVITY BY TREATMENT WITH PROTEASES -MECHANISM OF ACTION

The effects of protease digestion on the polypeptide composition and o n the infectivity of striped bass virus, an aquareovirus, were examine d, Both trypsin and chymotrypsin enhanced the infectivity of the virus . Enhancement of infectivity was correlated with the digestion of the outer capsid protein, VP7. These studies support the assertion that VP 7 is the outermost capsid protein and suggest that VP4 and VP5 are exp osed on the outer surface of infectious particles. The possible role o f VP7 in the variation in virulence observed among aquareovirus isolat es is discussed.