A lymphoblastoid response of human foetal lymphocytes to ultraviolet-irradiated herpes simplex virus

Cultures of foetal lymphocytes were exposed to u.v.-irradiated herpes simplex virus (HSV). The cells responded with increased 6-3H-thymidine incorporation, the formation of clumps of enlarged lymphoblastoid cells and cell division. This response was first detected 3 to 4 days after exposure to virus material and was shown to be virus-dose dependent. The ability to stimulate foetal cells was considerably more u.v. resistant than infectivity. Two isolates of HSV type 2 (4663 and 37174), which had a high "transforming" ability, produced large numbers of non-infectious particles (particle: infectivity ratios in excess of 10(4)). The cells, which responded to u.v.-irradiated HSV with blastoid transformation, were associated with the non-E-rosetting (T-cell-depleted) subpopulation.