Removal of N-Linked Glycosylation Enhances PD-L1 Detection and Predicts Anti-PD-1/PD-L1 Therapeutic Efficacy

Reactivation of T cell immunity by PD-1/PD-L1 immune checkpoint blockade has been shown to be a promising cancer therapeutic strategy. However, PD-L1 immunohistochemical readout is inconsistent with patient response, which presents a clinical challenge to stratify patients. Because PD-L1 is heavily glycosylated, we developed a method to resolve this by removing the glycan moieties from cell surface antigens via enzymatic digestion, a process termed sample deglycosylation. Notably, deglycosylation significantly improves anti-PD-L1 antibody binding affinity and signal intensity, resulting in more accurate PD-L1 quantification and prediction of clinical outcome. This proposed method of PD-L1 antigen retrieval may provide a practical and timely approach to reduce false-negative patient stratification for guiding anti-PD-1/PD-L1 therapy. [Display omitted] •N-linked glycosylation of PD-L1 hinders its recognition by PD-L1 antibodies•Removal of glycosylation enhances anti-PD-L1 signal in a variety of bioassays•Patient sample deglycosylation prevents false-negative detection of PD-L1•Deglycosylated PD-L1 is a more reliable biomarker to guide immunotherapy Histological detection of PD-L1 may guide therapy with anti-PD-1/PD-L1 antibodies but some PD-L1-negative tumors respond to these treatments. Lee et al. show that enzymatic deglycosylation of tissue sections improves PD-L1 detection and its predictive value, and could potentially impact patient stratification.