As cellular immunity is generally believed essential in the host defense against spontaneously occurring neoplasm, extensive research has done on the effect of gamma-radiation on the immune function of cancer patient. However, little is known
concerning
the effects of radiation on the normal immune system.
This study was designed to evaluate the effects of inoziing radiation on the normal immune system, such as cellular and humoral immune responses of mice, in vitro lymphocyte functions and N cell activities. The Arthus reaction and DTH response of
mice
to SRBC were significantly inhibited when mice were irradiated before immunization, but markedly augmented cnly when mice were irradiated at low doses after SRBC. Radiation qiote inhibited the expression of DTH response in recipient mice which
had
been
locally transferred with spleen cells form SRBC-primed donor when recipient was simultaneously irradiated with local cell transfer. Spleen cells from irradiated and SRBC primed donor still suppressed the DTH response of recipient mice to SRBC
when
donor
cells were systemically transferred to normal syngeneic recipient. Exposuree of mouse to ionizing radiation did not change the primary and secondary antibody responses to thymus-dependent Ag(SRBC). In contrast, radiation enhanced both primary and
secondary antibody response to thymus-independent Ag(PVP) when mice were irradiated after SRBC, but reduced thse responses when irradiated before SRBC. In vitro irradiation did signigicantly inhibite the mitogen-induced proliferation responses of
human
T lymphocytes, the DNA synthesis and Ig secretion of human Bs cells. NK cell activities of mouse splenocytes, and migration abilities of chicken leucocytes, in a dose-dependent fashion. However, after exposure to ionizing radiation, the
lymphokine
production of Con A-activated T lymphocytes was enhanced at low dose(10Gy) but decreased at high dose(60 Gy), and the rosette-forming actibities of human lymphocytes was normal or near normal level of control.
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