Monoclonal antibody that blocks the Toll-like receptor 5 binding region of flagellin.

The conserved domain of bacteria-derived flagellin coupling Toll-like receptor 5 (TLR5) activates NF-κB and MAPK signaling transductions, which subsequently regulate the transcription and expression of genes encoding immune mediators. However, whether the flagellin binding monoclonal antibody (MAb) obstructs TLR5-associated signaling is unclear. Here we report on the production and characterization of MAb 5G10 that specifically recognizes flagellin. The MAb 5G10 was produced by the hybridization of mouse myeloma cell SP2/0 with splenocyte from a flagellin immunized BALB/c mouse. We observed that deletion of the conserved amino acid residues 89-96 made flagellin lose its capacity for binding 5G10. Additionally, MAb 5G10 remarkably suppressed the expression of cytokine IL8 of Caco-2 cell by blocking the flagellin-TLR5 signaling. Furthermore, this MAb would be useful for cytosolic localization of flagellin and would facilitate the elucidation of the physiological function of specific pathogen-associated molecular patterns.