Expression, purification and characterization of phosphatidylserine-targeting antibodies for biochemical and therapeutic applications.

The externalization of Phosphatidylserine (PS) from the inner surface of the plasma membrane to the outer surface of the plasma membrane is an emblematic event during apoptosis and serves as a potent "eat-me" signal for the efferocytosis of apoptotic cells. Although less well understood, PS is also externalized on live cells in the tumor microenvironment and on live virus-infected cells whereby it serves as an immune modulatory signal that drives tolerance and immune escape. Given the importance of PS in cancer immunology and immune escape, PS-targeting monoclonal antibodies have been characterized with promising immunotherapeutic potential. Here, we describe the cloning and characterization of a series of PS targeting antibodies and their potential use and utility in immuno-oncology.