[Dissociation of the mast cell-lymphocyte rosettes].

It is established that incubation of the mast cells and lymphocytes in vitro in the medium 199 at 4 degrees C promotes spontaneous formationof mast cell-lymphocyte rosettes. While incubating in medium 199 at 37 degrees C a considerable part of mast cell-lymphocyte rosettes irreversibly dissociate in contrast to E-rosettes. Loss of ability to the formation of rosettes is due to the loss of the corresponding complementary structures mainly by the mast cells.

[Blood thymus hormone content in different types of neoplastic process and its changes as a result of chemotherapy and surgical removal of tumors].

Levels of thymic hormones in blood serum were found to decrease during the development of Guerin's carcinoma, methylcholanthrene- and DMBA-induced carcinogenesis, soft tissue sarcomas, mammary cancer, in children with tumors of the urinary-genital tract, that evidences for the suppression of the thymic endocrine function in neoplastic processes. A decrease in the level of substances, active in the test under study is not revealed in patients with different forms of leukemias. The tumour elimination normalizes the thymic endocrine function, while multiagent chemotherapy increases the insufficiency.

[Effect of thymus hormones on the capacity of lymphocytes for contact interaction with mast cells].

A study was made of the effect of thymostimulin, a medicine of thymus principles, on immature cells including also mastocyte-affined lymphocytes possessing membranous affinity to mast cells--the influence which may result in contact interaction of the above cell types with the formation of mastocyte-lymphocyte rosettes. The results obtained indicated that under certain conditions thymus principles influenced lymphocyte ability for contact interaction with mast cells.

[Mast cells and antitumor resistance].

Data on the possible participation of mast cells in the immunological surveillance are presented. Results of the investigations are adduced testifying to participation of mast cells as regulatory ones in the rejection of tumours by means of the development of the delayed hypersensitivity and as effector killer cells with cytolytic activity.

[Refractoriness of mouse spleen rosette-forming cells to thymus hormones during the period of early postnatal ontogeny].

The content of thymic serum factor in mice during the early postnatal ontogenesis is at the level characteristic of immunologically mature animals. Their spleen rosette-forming cells are, however, much less sensitive to antilymphocytic serum than those of adult animals. The sensitivity to the latter did not increase after incubation of splenocytes with thymosin or upon its multiple introduction to the neonatal mice.

[Contact interaction of mast cells and lymphocytes during ontogenetic antigen-induced differentiation and malignant transformation of lymphoid cells].

Mastocytes of newborn rats as well as those of adult ones are capable of rosette-formation, whereas the ability of lymphocytes to from rosettes increases with age. The thymocytes of 3-month-old mice lose the ability to mastolymphocytic rosette-formation (MLR) after priming for one hour at 45 degrees C. The ability of thymocytes and splenocytes to MLR-formation is closely related to the time course of immunization of the animals and the method of immunization.