Royal jelly fatty acids modulate proliferation and cytokine production by human peripheral blood mononuclear cells

Abstract

Royal jelly (RJ) fatty acids have recently been shown to possess various pharmacological and biological activities. In this work, we studied the immunomodulatory effects of 10-hydroxy-trans-2-decenoic acid (10-HDA) and 3,10-dihydroxy-decanoic acid (3,10-DDA), isolated from RJ, using a model of phytohaemagglutinin-activated human peripheral blood mononuclear cells (PBMCs). We showed that higher concentrations (500 μM) of both fatty acids inhibited the proliferation of PBMCs, and the process was followed by a decrease in the production of interleukin-2 (IL-2). 10-HDA at the concentration of 500 μM inhibited the production of IL-1β and tumor necrosis factor-α by stimulated PBMCs, whereas the same dose of 3,10-DDA had no effect on the levels of these cytokines. Regarding T helper (Th) cytokine profile, higher concentration of 10-HDA, in contrast to the lower one (50 μM), inhibited both Th1 and Th2 response, whereas Th17 response was not significantly modulated, as judged by the levels of interferon-γ, IL-5 and IL-17A in culture supernatants, respectively. Lower concentration of 3,10-DDA stimulated Th1 and Th17 responses and inhibited IL-10 production, whereas the higher dose augmented the Th2 response. In conclusion, our results showed a significant, dose-dependent, immunomodulatory effect of RJ fatty acids in vitro, which was also associated with their structure. © 2014 Springer-Verlag Berlin Heidelberg.