Preincubation of HD11 macrophages with anti-TLR15 antibody decreases MDLP-stimulated NO response. HD11 cells were preincubated with rabbit polyclonal anti-TLR15 antibody, normal rabbit serum (rabbit IgG) or phosphate buffer (PBS) for 1 h and then stimulated with NAP or MDLP for 24 h. Nitrite concentration in cell culture supernatants was measured by Griess assay. PBS-pretreated cells were used as control. Bars show mean ± S.E. (n = 3); ***, p < 0.001.