Description
Human monocyte THP-1 cells obtained from ATCC were cultured in RPMI 1640 (Invitrogen, Carlsbad, CA) containing 10% FBS and supplemented with 10 mM Hepes (Gibco BRL). THP-1 was differentiated into macrophages by 24-h incubation with 160 nM phorbol 12-myristate 13-acetate (PMA; Sigma, St. Louis, MO) followed by 24-h incubation in RPMI medium. Macrophages were further polarized to M1 macrophages by incubation with 10 pg/ml of lipopolysaccharide (LPS; Sigma) and 20 ng/ml of interferon (IFN)- (R&D Systems, MN) and are referred to as M(LPS+IFN-) cells. M2 macrophages were obtained by incubation with 20 ng/ml of interleukin (IL)-4 (R&D Systems) and are referred to as M(IL4) cells. To test the represented polarization marker of PMA differentiated-THP-1 macrophages stimulated with 20 ng ml(-1) IFN + 10 pg ml(-1) LPS and 20 ng ml(-1) IL-4, which are known to influence macrophage polarization in vetro into the M1 and M2 state, respectively.