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Immunological reactivity to hepatoma 22a was studied in newborn and adult mice pretreated with tumour antigens. Treatment of newborn mice enhanced the growth rate of hepatoma 22a. Analogous treatment of adult mice resulted in the immunization effect. Evidently this difference was connected with a possible change of immunological reactivity to the tumour in newborn mice. This is supported by the results of cell dynamics--a mediated immunity assessed by the macrophage migration inhibition test. Splenic cells of the pretreated adult mice possessed the capacity to depress the macrophage migration more intensively in comparison with those of the pretreated newborn mice.

The activity of acid phosphatase and some dehydrogenases in the peripheral blood lymphocytes was compared with the development of cell immunity, assessed by the macrophage migration inhibition test, during chemical carcinogenesis in Wistar rats. At the early stages of the carcinogenesis the changes of the enzymatic activities of succinic dehydrogenase and acid phosphatase proved to coordinate with a sufficiently high level of the immunological reactivity of the cell type in 66% of the animals. With the progressive growth of the tumours there occurred a disturbance of the enzymatic balance in the lymphoid cells and a simultaneous decrease in the immunological response.

The state of cell population of the lymph nodes and the thymus was studied on a model of rat sarcoma of the hip(induced by dimethlbenzanthracene) by the method of fluorescent sounds. Statistically significant changes of incorporation of the negatively charged sound 1-anilino-8-naphthalinosulfonate (ANS) into cell suspension, depending on the stage of sarcoma development, were detected. The appearance of cell forms with a lesser hydrophobic character of the surface and with less binding points for the ANS were noted at the early carcinogenesis periods. It is supposed that these cells were referred to immature ones. A conclusion was drawn on the applicability of the method of fluorescent sound for recording changes in the immunological state of the organism in carcinogenesis.

The effect of vibrio cholerae neuraminidase (VCN) on the growth of dimethylbenzanthracene-induced sarcoma cells in the inbred CBA mice was investigated. The use of this preparation was started after the appearance of the tumour. Injection of 50 units of VCN twice a week for three months was effective at the early stages of carcinogenesis. An increase of the life-span of mice of comparison with control animals was also observed in the animals inoculated intraperitoneally with induced syngeneic sarcoma cells pretreated with VCN and simultaneously injected (into the developing tumour) with sensitized lymphocytes received from the syngeneic tumour-bearing mice. Lymphocytes were inoculated into the growing tumour. No positive effect ensued when the lymphocytes inoculated into the tumour region were pretreated with VCN. A simultaneous inoculation of neuraminidase into the growing tumour and of syngenous induced-sarcoma cells pretreated with this enzyme intraperitoneally was the most effective. Possibilities of application of neuraminidase under clinical conditions are discussed.

The role of adhesive fraction of T lymphocytes in nonreactivity of mice to hepatoma 22a was studied. It was shown that the removal of the adhesive fraction from the spleen suspension enriched with T lymphocytes promotes intensification of cell immunity in tumor-tolerant mice.

Embryogenesis process is disturbed under the action of prolonged morphine administration to CBA mice. Simultaneously a decrease in the level of antibody-synthesizing cells and a significant reduction in the cooperating interaction of T and B lymphocytes in response to the injection of sheep red blood cells are noted. At the same time stimulation of bone marrow cells and specific sensitization of MIF-inducers to the antigen from the brain of morphinized mice are revealed.

As a result of the complex immunobiological study in an autologous system on the models of DMBA induced tumors in muscular tissue there were shown 3 types of cell response to primary tumors, their metastases and autotransplantation: no response, moderate and very pronounced reaction. In a definite percentage of cases autologous peritoneal macrophages were found to inhibit malignant cells in autotransplantation. The percentage of positive inoculations and an average weight of transplants of primary tumors and their metastases at the moment of highest transplantation immunity (12-14 days) have been definitely correlated with the intensity of cell response developed in these tissue, and also are dependent on individual features of proper malignant cells.

A comparative study was made of the percentage of cells bearing the receptor for the third component of the complement (LRC) and of the total cell content in the rat lymphoid organs as related to the time course of cancerogenesis. It was shown that impairment of the maturation processes in the thymus and in the peripheral organs (lymph nodes, blood) of the immunocompetent systems produces changes in intercellular interactions, reflected by accumulation of B cells, i. e. LRC, and their delayed maturation to antibody producers.

It was found that adoptive transfer of T lymphocytes from tumor-tolerant ice result in the enhancement of hepatoma 22a growth. This finding suggests an activation of suppressor cells. However, this activation is detectable only in the definite period during the immunologic tolerance induction.

Gel precipitation and immunoelectrophoresis have demonstrated the presence of thermostable tumour-associated antigens in blood serum from tumour-bearing rats and culture supernatant of malignant cells. These antigens have the electrophoretic mobility in the zones of beta-, alpha- and alpha 1-globulins.

Agglutination, gel precipitation and immunoelectrophoresis tests demonstrated the presence of antigens common for the Mycobacterium bovis (BCG) and some malignant and normal rat tissue cells. The method of absorption of immune sera in the agglutination test showed that this antigen was specific for the BCG microorganisms and cells of primary induced tumours of rat muscle tissue. This antigen had the electrophoretic mobility in the beta-globulin zone.

Gel precipitation and immunoelectrophoresis tests tests demonstrated the presence of thermostable antigens in dimethylbenzanthracene-induced malignant tumours of the muscle tissues of Wistar rats. These antigens were relatively tissue-specific for the tumours, amniotic fluid and the uterus on the one hand, and for the lung, spleen, and the serum on the other hand. The thermostable antigens of the tumours and the amniotic fluid had the electrophoretic mobility in the zone of alpha and alpha1-globulins.