Recombinant FliC and truncated FliC expressed from plasmid pORI induce TNF-α in a TLR5-dependent manner.
TNF-α ELISA of cell culture supernatants collected from TLR5-positive RAW424 (Blue) or its parental TLR5-negative RAW264.7 (Red) mouse macrophage cells. (A) RAW cells were treated with increasing concentrations of recombinant FliC. (B) Telomerized rhesus fibroblast cells were transiently transfected with plasmids containing full-length FliC (pORIfliC) or partially truncated FliCs (pORIfliCΔ196–378 or pORIfliCΔ141–398) and freeze thaw lysates were generated. Cell culture supernatants harvested from RAW cells treated with these lysates were assayed by an ELISA that measures TNF-α production. An average of two independent experiments and means with standard deviation are presented.