ABSTRACT
This chapter focuses on the influence of ultraviolet B (UVB) radiation on T-cell-mediated immune responses initiated in skin. Among experimental models of T-cell-mediated immunity, UVB-induced suppression of allergic contact sensitivity has been the most extensively investigated. Allergic contact sensitivity represents an animal model of a delayed-in-time, T-cell-mediated reactivity that is produced by cutaneous application of certain reactive chemicals (haptens) capable of binding directly to soluble and to cell-associated proteins. T-cell-mediated immune responses are suppressed by UVB radiation. The birth of photoimmunology as a modern science was heralded by the observation that the immune system plays a key role in preventing the growth of UVB radiation-induced skin cancer. This concept has since spawned numerous studies that have yielded a fuller understanding not only of photocarcinogenesis but also of the effects of UVB radiation on the immunologic functions of epidermal cells, particularly of Langerhans cells and keratinocytes.
