Two phenotypically distinct T cells (Ly1+2- and Ly1-2+) are involved in ultraviolet-B light-induced suppression of the efferent DTH response to HSV-1 in vivo.

We have previously demonstrated that the delayed-type hypersensitivity (DTH) response to herpes simplex virus type 1 induced by subcutaneous injection with live virus was suppressed by irradiating mice with a low dose (96 mJ/cm2) of ultraviolet-B (UV-B) light 3 days before sensitization. In order to determine the nature of the suppression, cells from mice irradiated with UV-B before immunization with live virus were transferred to syngeneic animals that had been sensitized with live virus without prior UV-B exposure. Efferent suppression of DTH to HSV-1 was shown to be due to T lymphocytes, and two phenotypically distinct T cells were involved: an Ly1+2- subset and an Ly1-2+ subset.