Recombinant human il 37 rhil 37

THP1 monocytes were suspended in complete medium, consisting of RPMI 1640, 2 mM L-glutamine, 100 units/ml of penicillin, 100 μg/ml of streptomycin, supplemented with 10% fetal bovine serum (FBS) (Gibco BRL, Grand Island, NY, USA) and were seeded in 24-well culture plates (2 × 10⁵ cells/ml/well). Cells then were treated with 50 ng/ml phorbol myristate acetate (PMA) for 24 h to generate THP-1-derived macrophages [2 (link)]. THP-1-derived macrophages were treated with or without 10 ng/ml recombinant human IL-37 (rhIL-37; R&D Systems, Minneapolis, MN, USA) for 3 h, followed by incubation for 1 h with or without a small-molecule inhibitor of Mertk (Mertk inhibitor UNC2250, 20 nM; Selleckchem, Houston, TX, USA) and then incubated with either 1 μg/ml lipopolysaccharide (LPS) (Sigma), 5 mM ATP (Sigma), or MSU (50 μg/ml, 100 μg/ml) separately for a further 18 h. Culture supernatants were harvested and frozen at −80 °C for later cytokine analysis by ELISA.