Effects of fission-neutron irradiation on proliferation of lymphocytes in murine spleen

The proliferative function of splenic lymphocytes in mice irradiated with graded doses of fission neutron was investigated 24h after radiation, using the method of 3H-TdR incorporation after mitogen stimulation. At the same time, the characteristics of injury and repair of proliferative function after 2.3 Gy neutron irradiation were compared with those after equivalent lethal dose of 60Co γ rays. The changes in the number of murine splenic lymphocytes indicate that there are two components in it: the radiosensitive and radioresistant to neutron radiation and γ-radiation, the radiosensitivity to neutrons is higher than that to γ-rays in the same component. D0 values of the radiosensitive cells to neutrons and to γ-rays are 0.40 Gy and 0.96 Gy, respectively. Therefore, RBE = 2.40. After radiation the proliferative response curves of splenic lymphocytes stimulated by ConA or by LPS show that both of T and B lymphocytes consist of two different radiosensitive components. D37 value of T cells which possess high sensitivity to neutron irradiation is about 0.82 Gy, that of B cells about 1.05 Gy. D37 values of T cells and B cells to γ-rays are 0.75 Gy and 2.38 Gy, respectively. Hence, RBE values are 0.91 and 2.27, correspondingly. After irradiation of 2.3 Gy fission-neutrons or 4.5 Gy γ-rays, the tendency of damage and recovery of the transformation function of murine splenic T lymphocytes stimulated by ConA is about the same, and that of B lymphocytes stimulated by LPS has the same pattern