title: Development of a sandwich ELISA for evaluating soluble PD-L1 (CD274) in human sera of different ages as well as supernatants of PD-L1+ cell lines.
abstract: PD-L1 (CD274) is a critical membrane-bound costimulatory molecule that inhibits immune responses through its receptor, PD-1. Previous data have showed that this molecule is associated with autoimmune diseases, chronic viral infections and tumor immune escape. However, the existence and role of soluble form of human PD-L1 (sPD-L1) remain unknown. We show here that a novel enzyme-linked immunosorbent assay (ELISA) was developed to detect the sPD-L1 protein. Many culture supernatants of the PD-L1+ cell lines contain high levels of this factor. Interestingly, the sPD-L1 is detectable in human serum and the concentration increases in an age-dependent manner. Human sPD-L1 has a unique protein form in the serum and the matrix metalloproteinase inhibitor (MMPI) could suppress sPD-L1 production. Moreover, the sPD-L1 could specially bind to PD-1. Together, these data demonstrate that the existence of circulating sPD-L1 in human serum might play an important role in immunoregulation.
authors: Department of Immunology, Medical College of Soochow University, and Clinical Immunology Lab, the First Affiliated Hospital of Soochow University, Suzhou, PR China.
authors: Yongjing
authors: Y
authors: Chen
authors: Qin
authors: Q
authors: Wang
authors: Bimin
authors: B
authors: Shi
authors: Ping
authors: P
authors: Xu
authors: Zhenhua
authors: Z
authors: Hu
authors: Lixiong
authors: L
authors: Bai
authors: Xueguang
authors: X
authors: Zhang
mesh_terms: D000367:Age Factors; D000818:Animals; D060890:B7-H1 Antigen / Q000097:blood*; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D020781:Matrix Metalloproteinase 1 / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D015203:Reproducibility of Results; D019139:Tumor Escape
chemical_list: D060890:B7-H1 Antigen; C423236:CD274 protein, human; C498919:Cd274 protein, mouse; D020781:Matrix Metalloproteinase 1