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

作者：Chen, Yongjing; Wang, Qin; Shi, Bimin; Xu, Ping; Hu, Zhenhua; Bai, Lixiong; Zhang, Xueguang^*

来源：Cytokine, 2011, 56(2): 231-238.

DOI：10.1016/j.cyto.2011.06.004

• PD-L1
• Soluble
• ELISA
• Expression

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 5PD-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.

• 出版日期2011-11
• 单位苏州大学