Histol Histopathol

Original Article Open Access

Novel PD-L1 mAb HC16 reveals upregulation of PD-L1 in BAC subtype

Bor-Chyuan Su1*, Chen-Hung Ting2*, Kang-Yun Lee3,4,5, Sheng-Ming Wu4,5, Po-Hao Feng4,5, Yao-Fei Chan4 and Jyh-Yih Chen2,6

1Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei City, 2Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Jiaushi, Ilan, 3Graduate Institute of Clinical Medicine, College of Medicine, 4Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, 5Division of Pulmonary Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei City and 6 The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung City, Taiwan
*equal contribution


Corresponding Author: Jyh-Yih Chen, Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, 23-10 Dahuen Road, Jiaushi, Ilan 262, Taiwan. e-mail: zoocjy@gate.sinica.edu.tw


Summary. Programmed death-ligand 1 (PD-L1) is an inhibitory transmembrane protein that can prevent autoimmune response. Upregulated PD-L1 serves as a predictive biomarker for patients who may respond well to immune checkpoint therapies. However, variable associations of PD-L1 level with prognoses have been reported. In this study, a short peptide sequence corresponding to PD-L1 amino acids 172-187 (from the extracellular Ig-like C-type domain, and with high predicted antigenicity and hydrophilicity) was used to generate a monoclonal antibody (mAb). The resultant PD-L1 mAb, clone HC16, was examined for binding specificity and reactivity in cancer cell-lines, as assessed by immunocytochemical, immunoblotting, and co-immunoprecipitation. The potential diagnostic and clinical applicability of clone HC16 was further tested using malignant tissue arrays derived from various cancer types analyzed with an automated immunohistochemical (IHC) staining platform. Additionally, tumor samples from patients diagnosed with non-small cell lung cancer (NSCLC) were analyzed by western blotting. Clone HC16 showed obvious staining activity in lung and breast cancer tissues. Interestingly, we observed that PD-L1 level was negatively associated with clinical stage in NSCLC. Strong PD-L1 expression tended to be found in patients diagnosed with bronchioloalveolar carcinoma (BAC). These results demonstrate that clone HC16 harbors good target specificity and is suitable for further development in diagnostic tools to assess PD-L1 expression in human tissues. In addition, our findings also suggest a role for PD-L1 in a non-invasive subtype of lung cancer. Histol Histopathol 36, 77-89 (2021)

Key words: Programmed death-ligand 1, Monoclonal antibody, Non-small cell lung cancer (NSCLC)

DOI: 10.14670/HH-18-272


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©The Author(s) 2021. Open Access. This article is licensed under a Creative Commons CC-BY International License.