Demchenko D. Intercellular interaction as a mechanism of іnfluence on the immunobiological and regenerative activity of hematopoietic and thymic multipotent stromal cells

The dissertation is devoted to the study of the influence of intercellular interaction on the immunobiological and regenerative activity of hematopoietic cells and multipotent thymic stromal cells (tMSCs). It was identified that the former physical interaction conferred new immunocorrective properties to cell grafts. Аll types of stromal cells had an ability to interact with the lymphoid cells derived from different sources (thymocytes, splenocytes, cells of the lymph nodes and bone marrow). The largest number of intercellular associations has been formed with the thymocytes, and the smallest one — with the lymphoid cells of bone marrow. Among differentiated forms osteogenic cells are capable of creating a higher number of intercellular associations, as compared to adipocytes. Thus, the possible intercellular physical interactions between the tMSCs and hematopoietic cells might be used as one of the new approaches for efficient and directed modification of the cell properties. The physical interaction of thymic stromal cells with thymocytes but not with bone marrow cells (BMCs) after 24 hours incubation potentiates the osteogenic differentiation and has no effect on the adipogenic cells maturation. tMSCs transplantation had a stimulating effect on lymphoid organs and on the functional activity of innate and adaptive immunity in mice after cyclophosphamide treatment: normalization increased by 2,9 times bactericidal activity of peritoneal macrophages, stimulated the natural cytotoxicity of splenocytes by 2,7 times and stimulation of normal phagocytic activity of peritoneal macrophages by 1,9 times and cytotoxic activity of splenocyte by 3 times, increase in the number of antibody-producing cells in the spleen by 1,8 times compared with the group of mice receiving CP. Transplanted BMCs improved erythropoiesis, which was manifested by the normalization of hematocrit and hemoglobin and an increase in the number of reticulocytes in the blood by 2,2 times compared with the group of mice treated with cyclophosphamide. Transplantation of BMCs did not affect the functional activity of the immune system. Meanwhile, tMSCs reduce the level of reticulocytes by 3,5 times.