Methods for selecting antibodies that specifically bind glycosylated immune checkpoint proteins

Abstract

Methods for producing and screening for antibodies that specifically bind to glycosylated immune checkpoint proteins (ICPs) relative to non-glycosylated ICPs are provided. Such antibodies recognize specific epitopes of glycosylated ICPs and can prevent or block the binding of a glycosylated ICP with its ligand, such as another ICP, and can inhibit the interactions between the two proteins that can lead to immunosuppression, as exemplified by the human PD-L1/PD-1 interaction. By way of specific example, human PD-L1 and PD-1 polypeptides comprising glycosylated amino acid residues within their extracellular domains are provided for generating anti-glycosylated PD-L1 or anti-glycosylated PD-1 antibodies that specifically bind PD-L1 or PD-1, respectively, and inhibit the PD-L1/PD-1 interaction. The antibodies produced and selected by the methods are especially useful as cancer therapeutics for disrupting, blocking, or neutralizing the ICP system and specific ICP interactions therein.