Rabbit monoclonal anti-programmed death-ligand 1 (anti–PD-L1) antibodies clone 28-8 and E1L3N both demonstrated PD-L1 target specificity (E1L3N, only at the plasma membrane).

Sensitivity of the two antibodies was comparable when an identical immunohistochemical retrieval and detection method was used; however, detection significantly improved with 28-8 versus E1L3N using manufacturer-recommended methods specific for each antibody.

Epitope retrieval and sensitive detective reagents are important for achieving optimal target specificity and sensitivity.