Effect of tripeptides on lymphoid and stem cells.

Tripeptides T-36 and, particularly, T-38 in concentrations of 0.1, 1, and 10 ng/ml inhibited proliferation of primary trypsinized embryonic mesenchymal stem cells, rat transplantable KF-1 fibroblasts, and human erythromyelosis K-562 cells. Inhibition of proliferation in embryonic and immortalized cells under the influence of tripeptides probably reflects antitumor activity of these substances. Tripeptides had no effect on lymphocyte survival and their adhesive, cytotoxic, and induced proliferative activities. T-36 did not modulate the proliferative properties of erythromyelosis K-562 cells. Tripeptides did not change engulfment activity and spontaneous and induced bactericidal activities of granulocytes. T-36 in a concentration of 0.1 ng/ml increased spontaneous proliferation of normal lymphocytes. These data suggest that tripeptides stimulate nontumor immune cells in adult people.