[An immunomorphological study of the effect of ionizing radiation on the nonlymphoid structures of the mouse thymus using monoclonal antibodies]. / Immunomorfologicheskoe izuchenie vliianiia ioniziruiushchei radiatsii na nelimfoidnye struktury timusa myshei s pomoshch'iu monoklonal'nykh antitel.

Expression of cytoskeleton components revealed with monoclonal antibodies was increased in epithelial cells of mouse thymus one day after total gamma-irradiation with doses of 0.5-4.0 Gy, while after the doses of 10 and 15 Gy it was decreased. The antigen expression was reversed to initial level 14 days after the dose of 4 Gy; thymocyte depletion was progressed and continuous massifs of epithelial cells was formed. The oval cysts and immunoglobulin deposits were appeared in thymus two months after irradiation with the dose of 4 Gy.

[Serum levels of thymus hormones and autoantibodies to the thymus epithelium in inhabitants of regions contaminated with radionuclides]. / Soderzhanie gormonov timusa i autoantitel k épiteliiu timusa v syvorotke krovi zhitelei raionov, zagriaznennykh radionuklidami.

Increased level of serum thymic activity and normal serum concentration of alpha-1-thymosin were revealed in inhabitants of region polluted by radionuclides after Chernobyl accident (settlement Vyshkov, Bryansk region). In the same population the serum level of autoantibodies, reacting with thymic epithelial cell line was elevated. Similar but less prominent alterations were found in population of radiologically pure region (settlement Potchep). Revealed autoantibodies had mainly IgM isotype. The negative correlation exists between levels of autoantibodies and serum thymic activity. Sera of persons from the control group and one half of Vyshkov inhabitants reacted with thymic epithelial cells of both human and mouse origin; in other half of Vyshkov inhabitants species-specific autoantibodies were revealed. We propose that correlated increase of antithymic autoantibody level and decrease of serum thymic activity are the consequence and indicators of unfavorable ecological conditions; however the contribution of radiation factor to their induction can not be estimated on the basis of presented data.

[Autoimmune disorders in liqvidators 11 years after the Chernobyl accident]. / Autoimmunye sdvigi u likvidatorov cherez 11 let posle avarii na ChAES.

We studied long-lasting consequences of the low-doses irradiation on the immune system of 71 clean-up workers who participated in the emergency work after the Chernobyl Plant accident in 1986 and 25 healthy donors from Belarus. In sera of the workers the level of autoantibodies to thyroid gland antigens (thyroglobulin and microsomal fraction of thyroid gland) was increased in 48% of cases, the level of autoantibodies to lens oculis antigen was increased in 44% of cases; the level of circulating immune complexes was elevated in 55%, and the serum level of thyroglobulin in 60% of people. Immunological disorders were found without any definite clinical evidences of diseases and this allows us to consider the examined contingent as a group of risk for the development of autoimmune pathology in the future.

[Changes in the immune system of the victims of the action of the factors in the accident at the Chernobyl Atomic Electric Power Station. Their manifestations, nature and the possible sequelae]. / Izmeneniia v immunnoi sisteme postradavshikh ot deistviia faktorov avarii na ChAES. Proiavleniia, priroda, vozmozhnye posledstviia.

The hypothesis is formulated, which explains genesis of long-lasting disturbances in the immune system of the persons affected by factors of Chernobyl disaster. Immunological alterations which are displayed at the late time after action of radiation in doses 0.5 Gy or lower are not a result of direct damage of the cells of immune system by irradiation. Their development is more probably a result of appearance of some systemic conditions and factors in affected organism--such as hormonal disbalance and especially autoantibodies of different specificities, including those reactive with thymic epithelial cells. Autoantibodies of the last type induce the decrease of thymic hormone secretion which results in functional deficiency of T lymphocytes. This chain of events is similar to those occurring in aging and does not directly causes development of the clinical displays of immunodeficiency. Only irradiation in doses of 4-6 Gy or higher inducing the structural damage of thymic microenvironment can rouse the long-lasting T cell immunodeficiency with the clinical manifestations.

[The effect of gamma irradiation on the proliferative activity of the cambial epithelium in a culture of thymus stromal cells]. / Vliianie gamma-oblucheniia na proliferativnuiu aktivnost' kambial'nogo épiteliia v kul'ture stromal'nykh kletok timusa.

A study was made of the effect of gamma radiation on proliferation of thymus stroma epithelial cells (EC) of newborn mice (CBA x C57Bl/6)P1 where EC content varied from 55% to 85%. EC proliferation was assessed 24 and 48 h after gamma irradiation by studying the mitotic activity of thymus EC and rate of MTT recovery (which permitted us to determine the nature of proliferating cells by their morphology). The quantitative characteristics of the two methods were identical. The effect of gamma radiation was assessed at various cultivation times. Irradiation at the time of inoculation reduced the proliferation of cells to logarithmic phase of growth. Irradiation with doses of 10 and 20 Gy after two-day cultivation inhibited proliferation of thymus EC and with 15 Gy increased the proliferative activity of thymus epithelium.

[Determination of autoantibodies to antigens of thymic epithelial cells of clean up team workers and patients who survived acute radiation sickness at distant periods after irradiation]. / Opredelenie autoantitel k antigenam épitelial'nykh kletok timusa u likvidatorov i bol'nykh, perenesshikh ostruiu luchevuiu bolezn', v otdalennyi period posle oblucheniia.

A group of patients, suffering from sequelae of acute radiation sickness (ARS), and liquidators was studied 5 years after exposure to a complex of factors resulting from the Chernobyl A.P.S. disaster. Studied were: the antibody titres to antigens of the cytoplasm of thymus epithelial reticulum cells and to Hassall's corpuscles the levels of serum immunoglobulins M, G, A; and the content of serum alpha 1-thymosin. Patients with ARS sequelae and liquidators showed a high level and incidence of autoantibodies to antigens of cytoplasm of thymus epithelial reticulum cells and to Hassall's corpuscles. There were no significant differences between the antibody levels in the blood of patients with ARS sequelae and liquidators. The antibodies were found to belong to IgM class; there was a correlation between the serum IgM titres and the rate of the indirect immunofluorescence reaction with autoantibodies to antigens of the cytoplasm of the thymus epithelial reticulum cells. To identify autoantibodies cryostat sections of human and mouse, (CBA x C57BL/6) F1, thymus as well as the epithelial and stromal cell culture of mouse thymus can equally be used.