MODULATION OF CYTOKINE PRODUCTION BY CARNITINE

THE ability of carnitine congeners to modulate cytokine production by human peripheral blood mononuclear cells (PBMC) was investigated. Modu lation of cytokine production by PBMC of young (30 years of age or you nger) and old (70 yeats of age or older) normal donors was first compa red. The PBMC were collected over Ficoll-Hypaque and incubated in the presence of various concentrations of acetyl L-carnitine for 24 h. Sub sequently the supernatants were collected and examined for cytokine pr oduction. The presence of cytokines in tissue culture supernatants was examined by ELISA. The cytokines measured included IL-1 alpha, IL-1 b eta, IL-2, IL-4, IL-6, TNF alpha, GM-CSF, and IFN gamma. The results s howed that at 50 mu g/ml of acetyl L-carnitine the most significant re sponse was obtained for TNF alpha. In this regard four of five young d onors responded, but only one of five old donors responded. More recen tly these studies were expanded to examine the ability of L-carnitine to modulate cytokine production at higher. doses, 200 and 400 mu g/ml, in young donors. The results of these studies showed that in addition to TNF alpha, significant production of IL-1 beta and IL-6 was observ ed. These preliminary studies provide evidence that carnitine may modu late immune functions through the production of selected cytokines.