Immunomodulation by some oligopeptides

The influence of bradykinin, some of its analogues, substance P and different partial sequences on lymphoid cells was studied under in vitro conditions. The oligopeptides bradykinin and substance P were found to be able to induce the secretion of charge-changing and chemokinetic lymphokines in very low concentrations. In each case, bell-shaped dose-response curves were registered in a concentration range from 10(-12) to 10(-6) M. An analysis of the lymphokine patterns suggests that T cells are the producer cells of charge-changing lymphokines. Comparing the structure-activity relationships of the peptides, the amino acid sequence Arg-Pro at the N-terminal region of bradykinin and substance P or Pro-Arg at the C-terminal part of tuftsin and rigin appear to be responsible for the lymphokine secretion.