[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.

[The induction of the migration of bone marrow stem elements to the periphery by the cytokines of cortisone-resistant thymocytes].

We present evidence about the functional activity of factors produced by cortisol-resistant thymocytes. Experiments in vivo have shown that the administration of the supernatant prepared from cortisol-resistant thymocytes leads to a strong stimulation of endogenous colony formation, significantly prolongs survival of sublethally irradiated mice, increases the rate of restoration of the number of thymocytes in the thymus after sublethal irradiation, and contributes to the recovery of the humoral immune response of nude mice to T-dependent antigens. The results obtained suggest that along with other cytokines, cortisol-resistant thymocytes spontaneously produce a chemotactic factor inducing migration of stem cells from the bone marrow to the periphery.

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.