Effects of host defense peptides B2RP, Brevinin-2GU, D-Lys-Temporin, Lys-XT-7 and D-Lys-Ascaphin-8 on peripheral blood mononuclear cells: Preliminary study

Abstract

Background and purpose: Host defense peptides have considerable therapeutic potential. One of the limitations for their therapeutic use is insufficient selectivity of some peptides, i.e. toxicity for eukaryotic cells. In this study, we have investigated effect of two naturally occurring and three analogs of frog skin-derived peptides on viability/proliferation of resting peripheral blood mononuclear cells and activated lymphocytes.

Materials and Methods: Effect of tested peptides was assessed using MTT colorimetric assay. Concanavalin A was used as lymphocyte mitogen.

Results: Brevinin-2GU induced cell death only in the highest tested concentration, whereas other peptides were not cytotoxic to resting peripheral blood mononuclear cells. Moreover, high concentrations of B2RP, D-Lys-Ascaphin-8  and Lys-XT-7 induced cell proliferation and this effect was more prominent in lymphocytes (p<0,05). Tested peptides had opposite effect on activated lymphocytes inhibiting proliferative response to Concanavalin A (Brevinin-2GU, B2RP and D-Lys-Temporin p<0,05).

Conclusions: Tested peptides (with exception of Brevinin-2GU) didn’t show cytotoxicity toward peripheral blood mononuclear cells. Moreover, they have potential to modulate immune response by inducing proliferation of resting peripheral blood mononuclear cells and limiting proliferative response to the activation stimulus. Regarding their potent antimicrobial and low hemolytic activity this makes them good candidates for therapeutic use.

Key words: host defence peptides; cytotoxicity; immunomodulation