FEDOSOVA N. Effect of Long-term Exposure to Small-dose Ionizing Radiation of the Anti-tumor Resistance

The thesis deals with investigation of the effect of changes in the immune homeostasis induced by a long-term exposure to combined irradiation in Ch.A.P.P. alienation zone on the anti-tumor resistance of experimental animals. It is shown that these changes stem from both somatic and genetic consequences of irradiation and arise in animals of various species and strains. The range, direction, and degree of these changes vary considerably depend upon the dose of irradiation, upon the duration of exposure, the stage of ontogenesis when this exposure began, and the presence or absence of exposure in earlier generations. At the early stages of exposure, the resistance to tumor growth was either unchanged or increased; at later stages it was decreased. The character of changes in the anti-tumor resistance induced by influence of a low-intensive ionizing irradiation was determined by the relationship between the impairment of various links of the immune system and compensatory/adaptive responses at differenttimes of exposure.