Nath, N, Godat, B., Zimprich, C., Dwight, S.J., Corona, C., McDougall, M., and Urh, M.
Notes: This paper describes a new method for assessing receptor-mediated antibody internalization, a key mechanism underlying several anti-cancer antibody therapeutics. The method allows uses a hydrophilic, bright pH sensor dye (pHAb dye), which becomes fluorescent at acidic pH. Upon antibody binding to a receptor, the dyes conjugated to the antibody are not fluorescent due to the neutral pH of the media environment. Upon antibody internalization and trafficking into endosomal and lysosomal vesicles, the pH drops and dyes become highly fluorescent. The authors show the effectiveness of the method using two different therapeutic antibodies – Trastuzumab (anti-HER2) and Cetuximab (anti-EGFR). (4633)