Immunocytochemistry analysis of CHO-PDL1 (PD-L1 stably expessed Chinese hamster ovary epithelial cell) labeling PD-L1 with purified ab205921 at 1/400 dilution. Cells were fixed with 4% Paraformaldehyde and permeabilised with 0.1% tritonX-100. Goat anti rabbit IgG (Alexa Fluor® 488, ab150077) at 1/1000 (2 µg/ml) was used as the secondary antibody. ab195889 Anti-alpha Tubulin antibody [DM1A] - Microtubule Marker (Alexa Fluor® 594) 1/200 (2.32 µg/ml) was used as counterstain. Nuclei were stained blue with DAPI. Negative controls: Cells not transfected with PD-L1, and both the transfected and mock tranfected cells without the primary antibody.

Immunohistochemical analysis of formalin-fixed paraffin-embedded human tonsil labelling PD-L1 with ab205921 at a dilution of 2µg/ml. The immunostaining was performed on a Ventana DISCOVERY ULTRA (Roche Tissue Diagnostics) instrument with an OptiView DAB IHC Detection Kit. Heat mediated antigen retrieval was conducted for 32min with ULTRA cell conditioning solution (CC1 pH8.5). ab205921 anti PD-L1 antibody was incubated at 37°C for 16min. Sections were counterstained is with Hematoxylin II. Image inset shows absence of staining in secondary antibody only control.