gp41 envelope protein of human immunodeficiency virus induces interleukin (IL)-10 in monocytes, but not in B, T, or NK cells, leading to reduced IL-2 and interferon-γ production

The effect of extracellular domain of human immunodeficiency virus (HIV-1) transmembrane glycoprotein gp41 on interleukin (IL)-10, IL-2, interferon (IFN)-gamma, IL-4, and tumor necrosis factor-alpha production by human peripheral blood mononuclear cells (PBMC) was assessed by ELISA. Rapid gp41-induced increase of IL-10 production was detected in resting PBMC and isolated monocytes but not in B, T, or Ne cells. Furthermore, gp41 also enhanced lL-10 production in staphylococcal enterotoxin B-stimulated PBMC, while synthesis of IL-2, IFN-gamma, and IL-4 in these cells was downmodulated. Kinetic studies revealed that increased IL-10 production preceded reduction of IL-2, indicating the possible IL-10 regulatory role in the gp41-induced down-modulation of this cytokine. Anti-IL-10 antibody reversed almost completely the gp41 inhibitory effect on IL-2 production. In this study, HIV-1 gp41 was a potent modulator of cytokine production by PBMC, in particular by increasing IL-10 secretion from normal monocytes/macrophages and consequently down-regulating IL-2 and IFN-gamma.