T-lymphocyte levels in the peripheral blood of gamma irradiated rhesus monkeys.

Circulating Thymus derived (T) lymphocytes were studied in Rhesus monkeys exposed to single whole body gamma radiation with doses of 400, 500 and 600 Rad. Spontaneous lymphocyte rosette assay (E-rosettes) was used to evaluate the level of T-lymphocytes. A decrease in total leukocytes, lymphocytes and T-lymphocytes levels was observed beginning from the 5th day after irradiation and continued for several weeks after radiation.