Studies on vaccinia virus plaque formation and its inhibition by interferon: I. Dynamics of plaque formation by vaccinia virus

Abstract

Plaques of vaccinia virus in chick embryo cell monolayers without agar emerged into visibility according to a normal sigmoid curve. The distribution of plaque diameters could be approximated by a normal Gaussian curve, with a variable proportion of plaques hidden below the threshold of visibility (infraplaques). Between 32 and 48 hours, and possibly up to 57 hours after inoculation, all plaque diameters increased linearly with time at the same rate. The total plaque area increased between 32 and 48 hours at an almost exponential rate. Strains of vaccinia virus differ in the rate of appearance of primary and secondary plaques.