A Comparison Between Cell, Protein and Peptide-Based Approaches for Selection of Nanobodies Against CD44 from a Synthetic Library

BACKGROUND: The hyaluronic acid receptor CD44, is a cancer stem cell biomarker, playing important roles in cell adhesion, tumor progression and drug-resistance. Therefore, CD44 is a potential target for cancer treatment and its blockade could result in multi-factorial therapeutic effects. METHODS: Nanobodies against CD44 were isolated from a synthetic library with a diversity of 5×1011 CFU/ml using the phage display technique. Three approaches were used for isolation of nanobodies fragments including peptide-, protein- and cell-based panning. RESULTS: Nanobodies from cell-based panning displayed more specificity compared to protein or peptide-based panning. Our results show that cell-based panning is the most efficient method for isolation of a specific single domain antibody fragment to CD44 from a synthetic phage displayed library. CONCLUSION: The isolated nanobodies could successfully recognize and bind cells that express the CD44 surface antigen.