PROPERTIES OF CV-1-STRAIN OF VACCINIA VIRUS .I. STUDIES IN CELL CULTURE

In secondary rhesus monkey kidney and HEp-2 cells, CV1 produced the smallest, strain CL the intermediate and LCA the largest plaques. This was the same order as for rates of multiplication in monkey kidney cells, thereby suggesting that the rate of multiplication determined the plaque size. The plaque borders of the two unattenuated strains stained deeper with neutral red. In chick embryo fibroblasts CV1 produced the largest and LCA the smallest plaques. Compared with monkey kidney cells, the plaquing efficiency in chick embryo fibroblasts was 100% for CV1 but less than 40% for the other two strains. Screening studies did not suggest that increased induction of, or increased sensitivity to interferon in monkey kidney cells was related to the smaller plaque size or slower growth rate of the CV1 strain of vaccinia. © 1969 Springer-Verlag.