Successful acquisition of a neutralizing monoclonal antibody against a novel neutrophil-activating peptide, mitocryptide-1

• We generated NM1B1, a monoclonal antibody that specifically bound to mitocryptide-1.
• NM1B1 inhibited phagocytosis induced by mitocryptide-1 in neutrophilic cells.
• NM1B1 suppressed mitocryptide-1-induced migration of neutrophilic cells.
• NM1B1 was a specific neutralizing antibody against functions of mitocryptide-1.

Mitocryptide-1 (MCT-1) is a novel neutrophil-activating peptide derived from mitochondrial cytochrome c oxidase subunit VIII, and its physiological role and involvement in various diseases have not yet been elucidated. Generating neutralizing antibodies against the function of MCT-1 is of particular importance for investigating its physiological and pathophysiological roles, because MCT-1 is a fragmented peptide of its mother protein and hence it is very difficult to manipulate its expression level genetically without affecting expression of the mother protein. Here, we report the successful generation of a neutralizing monoclonal antibody (MAb) against MCT-1. This MAb, designated NM1B1, which specifically bound to the region of positions 9–22 of MCT-1, showed concentration-dependent inhibition of MCT-1-induced migration and β-hexosaminidase release in neutrophilic/granulocytic differentiated HL-60 cells. Thus, NM1B1, as a neutralizing MAb against MCT-1, could elucidate not just the physiological regulatory mechanisms of MCT-1 but also its pathophysiological involvement in various inflammatory diseases in vivo.