EFFECTS OF IRRADIATION DOSES ON ALTERATIONS IN CYTOKINE RELEASE BY MONOCYTES AND LYMPHOCYTES

We evaluated the effect of increasing doses of gamma-irradiation on th e release of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) fro m lymphocytes, and interleukin 1beta (IL-1beta) and tumor necrosis fac tor-alpha (TNF-alpha) from monocytes. The most radiosensitive populati ons were the T lymphocytes which release IL-4 and IFN-gamma after irra diation alone. This release increased when the cells were activated by polyclonal activators such as Concanavalin A (Con A). Monocytes irrad iated and stimulated with lipopolysaccharide (LPS) released TNF-alpha with values near those of the control cells. Con A produced no effect. The release of IL-1beta decreased as the irradiation dose was increas ed, while stimulation with LPS and Con A caused a greater IL-beta incr ease after small irradiation doses. The results obtained show that min imum doses of irradiation can induce significant alterations in an amp lified and unbalanced immunologic response through release of cytokine s.