RIVM Report 850017002
As a result of a depletion of atmospheric ozone all living organisms on the earth's surface may be exposed to increased amounts of ultraviolet radiation. An elevated exposure to UV-B radiation may lead to an increased incidence of deleterious effects on human health. Our experiments showed that UV-B affects the resistance to infectious diseases in rats. In this study non-invasive methods were used to analyse the differences in susceptibility between man, rat and mouse for UV-B induced immunosuppression in order to extrapolate data from studies on the effect of UV-B on the resistance against infectious diseases in rats, to men. In this study particularly the effect of UV-B radiation on the Mixed Lymphocyte Reaction (MLR), which analyses specific activity of T cells, was determined. Lymphocyte Transformation Tests (LTT) were performed in order to analyse aspecific proliferation T lymphocytes. In vitro UV-B radiation suppressed the MLR responses of splenic lymphocytes of rats and mice, suppressed the MLR responses of blood lymphocytes of rats and humans and suppressed the LTT responses of splenic lymphocytes of rats (P<0.05). Splenic lymphocytes of rats may be more sensitive to UV-B radiation than splenic lymphocytes of mice (P<0.05). Peripheral blood lymphocytes (PBL) of rats were more sensitive to UV-B radiation than PBL of humans (P<0.05). The effect of UV-B radiation on the MLR is not only due to decreased vitality of the lymphocytes.