Application Note

Soluble PD-L1 Detection in Cellular Supernatants Using AlphaLISA


When PD-1, which is expressed on the T cell, binds to PD-L1 expressed on the tumor cell, the T cell response is suppressed. Utilization of this pathway leads to tumor immune escape and promotes tumor cell growth. In fact, PD-L1 expression increases with tumor severity in many types of cancer. Release of a soluble form of PD-L1 (sPD-L1) into circulation is one mechanism that tumors may use to evade the immune response; however, it is unclear whether sPD-L1 can bind PD-1 and deliver an inhibitory signal. Previous studies have shown that soluble forms of PD-L1 have been detected in supernatants of cancer cell lines.

Traditional methods for assessing soluble and membrane-associated PD-L1 are wash-based ELISA assays, which typically require 5-6 hours of assay time. AlphaLISA® technology provides a rapid, no-wash bead-based alternative to traditional ELISAs. In this Application Note, we demonstrate how AlphaLISA is used to detect the presence of PD-L1.