The interaction between PD-L1 (CD274/B7-H1) and its receptor programmed death-1 (PD-1) is not only a focus of cancer immunotherapy research but also has major therapeutic relevance for many solid malignancies. PD-L1 is an immune checkpoint inhibitor that binds to PD-1 expressed on T cells and other effectors to quash immune system overactivation and autoimmunity. Cancer cells exploit this and overexpress PD-L1, creating an immunosuppressive state through induced cell death of anti-tumor T cells. Thus, gauging PD-L1 expression on tumor cells can identify cancers that may respond to anti-PD-L1/PD-1 agents. Given the importance of PD-L1 detection in patient tumor samples for both prognostic and treatment considerations, reliable reagents are clearly essential for both research and clinical decision-making.

Immunohistochemistry is utilized routinely in both academic and clinical settings to determine PD-L1 expression in both normal and cancerous tissues. GeneTex's recombinant rabbit monoclonal antibody (PD-L1 antibody [HL1041]) is a cited, PD-L1-specific, knockout-validated reagent that performs in three applications (i.e., western blot, immunocytochemistry, and IHC). To further evaluate this antibody's IHC capabilities, GeneTex enlisted the assistance of MS Validated Antibodies GmbH (MSVA), a company with demonstrated proficiency in IHC optimization that has assessed over 5000 antibodies for their functionality in formalin-fixed tissue IHC. MSVA completed an extensive analysis of the GeneTex antibody's staining on tumor samples and a broad array of normal tissues, comparing the signal to that of another well-established PD-L1 antibody (see Figure). GeneTex clone [HL1041] exhibited excellent sensitivity and specificity. Marco Sauter, MSVA CEO, commented, "As formalin fixation alters the structure and accessibility of many epitopes, a trustworthy antibody validation for IHC invariably requires the analysis of a very broad range of formalin-fixed tissues. Our analysis of more than 70 different normal tissue types and of a broad range of different cancers exceeds what regulatory agencies currently require. We are gratified that our MSVA approach could help to identify PD-L1 clone [HL1041] with binding properties that are comparable to the most established PD-L1 antibodies on the market."

The need for quality antibodies to visualize the expression of biomarkers crucial for cancer biology research and patient care remains vast, particularly for IHC. GeneTex is presently developing reagents against a number of key targets. Allen Lee, GeneTex's Vice President of Business Development, stressed the importance of expertise-based collaborations to create gold-standard products for scientists and clinicians: "GeneTex is excited to extend our partnership with MSVA. Their IHC validation services align perfectly with GeneTex's core mission, which is to provide the biomedical community with the highest quality immunological reagents supported by extensive research, development, and validation."

GeneTex products are for research use only. Not for diagnostic or therapeutic procedures.