Figure 7. PS targeting agents 11.31 and Dimerized Annexin V suppress epithelial cell efferocytosis and PD-L1 expression.

A. Flow cytometry based binding studies of PS targeting agents to PS on live and apoptotic cells. UV treatment mediated apoptosis and PS exposure was measured by Annexin-V staining by flow cytometry. Anti-human PS targeting antibody 11.31 or Bavituximab were incubated with thus produced apoptotic or live cells using Annexin V as control. Percentage of PS targeting antibodies bound with apoptotic cells were measured with conjugated flow antibodies by flow cytometry. (B–E) PS targeting agents affect Gas6 and apoptotic cells induced TAM receptor activation. Effects of PS targeting 11.31 antibody (B–D) and dimerized Annexin V D19 (C–E) on Tyro3, Axl and Mertk receptor activation by apoptotic cells and Gas6 in TAM-IFN-YR1 chimeric receptor system. Effects of 11.31 PS targeting antibody (F) and Annexin V dimer D19 (G) on relative efferocytosis by MDA-MB-231 and HeLa epithelial cells. Role of 11.31 and Annexin V dimer D19 treatments on cell surface expression of PD-L1 by flow cytometric analysis in Gas6 and apoptotic cells induced MDA-MB-231 (H) and HeLa (I) cells. Western blots bands that are cropped are separated with dotted lines. (J) Schematic model representing different PS sensing and PS signal amplifications paradigms by TAM receptors.