EFFECT OF PROTEOLYTIC ENZYMES ON VACCINIA VIRUS REPLICATION

Chymotrypsin and trypsin enhance vaccinia virus replication in chick embryo cell cultures. Two phenomena are described: an enhancement of plaque numbers and an increase in plaque size. Low doses of chymotrypsin (1.3 μg/4 million cells) acting on the virus particles are responsible for the increase in vaccinia virus plaque numbers. The effect is not due to disaggregation of virus aggregates by the enzyme. Doses of 3 to 10 (μg of chymotrypsin per culture have an effect on chick embryo cell monolayers. A linear dose response is found when plaque size is measured as a function of the dose of chymotrypsin. Preliminary studies indicate that some of the enzyme becomes cell-associated. When one replication cycle was followed the final yield of plaque forming virus from both enzyme treated and control cells was the same. However, the process of replication in enzyme treated monolayers was accelerated by about 5 hours. The enzyme appears to have an effect on some early event in virus replication. © 1969 Springer-Verlag.