Abstract
The growth of Herpes simplex virus type 1 (HSV-1) in human lymphocytes of adult and foetal origin was studied. Virus DNA synthesis, antigen and particle production and the yield of infectious progeny were determined in cultured lymphocytes with or without exposure to stimulating concentrations of the mitogens phytohaemagglutinin and pokeweed mitogen. Separated sub-populations of cells were examined and the conclusion reached that only the stimulated T-lymphoblast was permissive for full virus expression.