VARIANTS OF HERPES SIMPLEX VIRUS: ISOLATION, CHARACTERIZATION, AND FACTORS INFLUENCING PLAQUE FORMATION.

Rapp, Fred (Baylor University College of Medicine, Houston, Tex.). Variants of herpes simplex virus: isolation, characterization, and factors influencing plaque formation. J. Bacteriol. 86:985-991. 1963.-Variants of herpes simplex virus were isolated which differed in plaque size and in virulence for rabbits and mice. Keratitis on the rabbit cornea and generalized disease were associated with the large, but not the small, plaque variants. The large plaque variants were about as neurovirulent as was the parent strain for weanling mice, but the majority of the small plaque variants were only 1% as virulent for mice as was the parent virus. Agar inhibited the formation of plaques by the parent strain and all variants tested; development of plaques was retarded and the number of plaques was approximately 60% less than those developing under an overlay in which methyl cellulose had been substituted for the agar. Rabbit kidney cells and human embryonic lung fibroblasts were more sensitive than mouse embryo fibrolasts to infection with all variants tested.