LPS induced TLR4 expression and associated with TLR4 in human chondrocytes. (A) Primary human chondrocytes were either left untreated (b, basal Co) or were treated with 10 ng/ml (c) or 100 ng/ml lipopolysaccharides (LPS) (d) for 12 h, then were immunostained with anti-Toll-like receptor 4 (TLR4) (red) and counterstained with DAPI (blue). Control, in which primary antibodies were replaced with control rabbit IgG (a). Results are representative of three experiments using human chondrocytes. Magnification x400; bar, 30 nm. (B) Lysates prepared from human chondrocytes exposed to LPS (100 ng/ml) or untreated (c) (negative control) were incubated with anti-LPS. Immunoprecipitates were analyzed by western blotting with anti-TLR4. Presence of band of the correct size (approximately 100 kDa) corresponding to chondrocytes treated with LPS confirms the binding of LPS to TLR4. The original samples were probed with an antibody to anti-TLR4. Data shown are representative of three independent experiments. IgH: immunglobulin heavy chain.
Lorenz et al. Arthritis Research & Therapy 2013 15:R111 doi:10.1186/ar4291