Proliferative activity and subpopulation pattern of cells in murine thymus and spleen on the model of graft-versus-host chronic reaction under various diurnal regimens of IL-2 administration.

We studied the effects of IL-2 administration at different times of day to female B6D2F1 mice with experimental immunopathology, graft-versus-host chronic reaction induced by the administration of lymphoid cells from parental female DBA/2 mice. Recombinant murine IL-2 was injected subcutaneously at 10.00 (group 1) or 16.00 (group 2) after the first cell transfer. Evening administration of IL-2 in contrast to its morning injection prevented cell proliferation in the thymus and spleen, decreased the number of apoptotic splenocytes, significantly stimulated differentiation processes in the thymus, increased the amount of CD4 (+) 25 (high) thymocytes, and decreased the number of CD4 (+) 27 (low) splenocytes. These findings can serve as a prerequisite for the development of chronotherapeutic schemes for immunocorrection.