2.4. Detection of TLR6 protein expression by immunofluorescence

SW480 (50,000 cells/well) and HT29 (30,000 cells/well) cells were cultured on poly l-lysine-coated cover glass slides in 24-well culture plates. After 24 h of incubation, the slides were washed twice with phosphate-buffered saline (PBS) for 3 min each and then fixed with 4% paraformaldehyde for 30 min at 4 °C. Then, TLR6 expression in SW480 and HT29 cells was detected using immunofluorescence staining. In brief, the cells were permeabilized, blocked, incubated with antibodies against TLR6 (InvivoGen, France) and the fluorescent secondary antibodies, and combined with the anti-fluorescence attenuation sealing solution (containing DAPI).