Effects of interleukin-7 on the maturation of human T-lymphocytes in vitro

We investigated the direct effect of interleukin-7 (IL-7) on the maturation of isolated human T-lymphocytes. Homeostatic model reflects the IL-7-mediated self-maintenance of the T-cell pool under physiological conditions. Activation model mimics the immune synapse formation with signal transmission from antigen-presenting cell to T lymphocyte under antigenic load. Culturing T-cell with activator resulted in a significant reduction in the number of T-helper effector memory cells and increased number of more mature subpopulations as compared to the intact probe. Adiministering of IL-7 to cells in the activation model resulted in the depletion of the pool of T-helper central memory cells, less differentiated compared to the T-helper effector memory cells, with increased number of more mature cells. In homeostatic culturing model IL-7 also reduces the number of T-helper central memory cells with an increase of terminally differentiated T-cells pool. Based on the fact that the addition of IL-7 leads to a decrease in the number of less mature cells with an increase in the number of cells that have lost their proliferative potential (as a result of terminal differentiation), we assume the role of IL-7 as maturation inducer for resting T-cells. At the same time, IL-7 effect on less differentiated subpopulation of T-cells in activation model allows us to consider IL-7 as the maturation accelerator for activated T-cells. In both experimental models the maturation of T-lymphocytes began from the stage of central memory cells.