Biologic Comparison of a Syncytial and a Small Giant Cell-Forming Strain of Herpes Simplex

Abstract

A syncytium-forming strain (HPF) and a small giant cell-forming strain (HF) have been isolated from a standard reference herpes simplex virus. Compared to HF, HPF is less virulent for mice, rabbits, chorioallantoic membrane and chick embryos; it is more rapidly inactivated by heat; there is more viral production in tissue cultures at lower temperatures; and there is a distinct but minor antigenic difference between the two. Both strains appear stable on serial passage and neither requires antibody in the culture medium for characteristic appearance in tissue cultures. The stability and reproducibility of plaque morphology and virulence of these strains can probably be exploited in studies of neutralization, viral genetics, immunity and giant cell formation.