[Influence of autocrine factor deficit in culture on survival and energy metabolism of CTLL-2 cells under oxidative stress].

A lot of data has shown recently that survival of mammalian cells is under a control of growth factors and autocrine survival factors (AF). We studied the influence of AF deficit on survival, intracellular ATP content, and transmembrane potential of mitochondria of IL-2-dependent CTLL-2 cells under oxidative stress. CTLL-2 cells cultivated under deficit of AF have been shown to be more susceptible to oxidative injury in comparison with the cells cultivated without deficit of AF (control); they died at smaller concentrations of H2O2 than control cells did.

Nanomolar concentrations of gangliosides stimulate primary humoral response.

Exogenous gangliosides act as immunosuppressors when applied at micromolar concentrations corresponding to their average level in human plasma. Here we show that at nanomolar concentrations the gangliosides GD3, GD1a and GM1 can act as immunostimulators markedly enhancing the number of plaque-forming cells in mouse splenocyte culture responding to sheep erythrocytes. At such low concentration these gangliosides as well as GM3 were not able to influence significantly proliferative responses of splenic B and T lymphocytes or of cytotoxic T-cells.

Comparative study of immunomodulatory properties of muramyl peptides on immune system cells of young and old mice.

The immunomodulatory effects of two synthetic muramyl peptides (MP): muramyl dipeptide and glucosaminyl- muramyl dipeptide have been compared. It was shown, that MP effects on immune response are a consequence of the alteration in T lymphocyte regulators balance. MP action on old mice immune response and lymphocyte function was stimulating only: increasing of T helper precursors frequency and IL-1 production by macrophages.

[The formation of T-suppressors that suppress the activity of alloreactive T-cells after lymphocyte interaction with 2 different thymus-derived mediators].

The data are presented on simultaneous interaction of thymocytes and T-cells from lymph nodes with two humoral factors produced by macrophages and epithelial cells, main stromal elements of the thymus. Such contact of T-cells with two mediators resulted in the formation of T-suppressors capable of inhibiting the activity of syngeneic allospecific T-lymphocytes. These T-suppressors did not alter the response to another antigen but inhibited proliferation of donor cells.

Study of immunomodulatory properties of N-acetylmuramyl-L-alanyl-D-isoglutamine and N-acetylglucosaminyl-(beta 1----4)-N-acetylmuramyl-L-alanyl-D-isoglutamine.

The immunomodulatory activities of two synthetic muramylpeptides (MP), a muramyl dipeptide and a glucosaminyl-muramyl dipeptide, have been compared and have been found to exhibit many common features in their effects. In addition, the differential effects of low and high concentrations of MP on the primary humoral immune response in vitro were examined in detail. At high concentrations MP augmented the frequency of induced T-suppressor cells, while at low concentrations the primary immune response was stimulated by enhancement of the antigen-presenting function of accessory cells and by increasing the frequency of induced T-helper cells.

[Specific interaction of phagocytosing mononuclears with T cells during formation of the thymocyte-induction factor].

Data are provided on specific secretion by macrophages of a factor inducing the functional differentiation of thymocytes. The contact of mononuclear phagocytes with lymphocytes of T-cell type induces the formation of this transmitter. Interaction of macrophages with B-cells does not lead to the secretion of this monokine.

[The role of major histocompatibility complex genes in the reaction of macrophages and thymocytes during induction of T-effectors of the graft vs host reaction. III. Effect of antisera against H-2 complex antigens on the realization of the process].

The data are presented on the influence of antisera to different products of the histocompatibility gene complex on the interaction between macrophages and thymocytes during the formation of T-cell GVH effectors. The intensity of the local GVH reaction was evaluated by the index of the lymph nodes enlargement. The close physical contact between cells was necessary for the induction of T-effectors GVH.

[Functional differentiation of thymocytes induced by macrophages: cellular, humoral and genetic aspects].

The cellular, humoral and genetical mechanisms of induction of T-effectors of the graft vs. host reaction (GHR) were studied in a double-cell culture of phagocytizing mononuclears with thymocytes. Experiments were carried out on mice of inbred and recombinant strains.

[Control by genes of the major histocompatibility complex of macrophage-thymocyte interaction during induction of T-effectors of graft versus host reaction. II. Analysis at the level of humoral factor activity].

The data are presented on the genetic restriction of interaction between humoral factors and intact thymocytes during the formation of T-cell effectors GVH from thymus cells. The source of humoral factors was a cultural medium from combined cultivation of macrophages and syngeneic thymocytes during 18 h. The intensity of the local GVH reaction was evaluated by the index of the lymph nodes enlargement.

[Control by major histocompatibility complex genes of macrophage interaction with thymocytes during induction of T-effectors of graft vs host reaction. I. Genetic control on the cellular level].

H-2 complex control of interaction between macrophages and thymocytes during induction of T-cell effectors GVH was studied. Intensity of the local GVH reaction was evaluated by the index of the lymph nodes enlargement. Genes of the H-2 system control interaction of macrophages with thymocytes during the formation of T-cell effectors GVH.

[Thymus target cells subject to the regulatory effect of macrophages during the formation of graft-versus-host reaction effectors].

The data are provided on the interaction of macrophages with different thymocyte subpopulations during the formation of T cells entering the graft-versus-host reaction (GVHR). The intensity of the local GVHR was evaluated from the index of lymph node enlargement. The cortisone-sensitive, relatively radioresistant cells lying in the thymus cortex and migrating to the spleen have been demonstrated to serve as targets for the regulatory effect of macrophages.