Identification of a peptide targeting CD56.

Neural cell adhesion molecule 1 (NCAM1/CD56) is expressed on immune cells, myoblasts, and malignant cells, and there is a growing demand for the genetic detection of CD56 and CD56-targeted therapy. In the present study, we developed a novel peptide ligand (designated Natein) that binds to human CD56 by using T7 phage display technology. Natein recognized the extracellular region of CD56 and could bind to natural killer (NK) cells and CD56-positive (CD56+) cancer cells. CD56+ cells enriched from human peripheral blood mononuclear cells (PBMCs) using biotinylated Natein-conjugated microbeads, similarly to CD56 antibody-isolated cells, demonstrated functional cytotoxicity against K562 cells. In addition, Natein could be used to stain CD56+ lymphoma cells in nasal-type extranodal NK/T-cell lymphoma tissues similarly to a CD56 antibody. These findings suggest that Natein has the potential to be alternative to CD56 antibody that could be used for peptide-based cell isolation and diagnosis.