Investigating the expression and function of nectin family members in anti-tumor immunity

Abstract

CD112R (Pvrig), is a newly identified member of the nectin family, of which there are nine in total including TIGIT and TACTILE. Members of the nectin and nectin-like families have been shown to perform a wide range of functions including immune surveillance, regulation of cell proliferation, and cell differentiation. In our preliminary analysis of single cell RNA seq datasets, Pvrig was found to be highly co-expressed with T cell inhibitory molecules including Pdcd1, Tigit, and Havcr2 in CD8+tumor infiltrating lymphocytes. In vivo studies utilizing Pvrig knock-out mice touched on its role in anti-tumor immunity, however little is known about its signaling pathways and regulators. The ligand for CD112R, CD112 (Pvrl2) is frequently expressed on myeloid cells and although it preferentially binds CD112R, it can also bind to DNAM-1 (Cd226) and TIGIT. Despite the high expression of CD112 on myeloid cells, the molecular mechanism and bi- directional signaling pathways subsequent to interaction between CD112 and CD112R are still insufficiently understood. In this project, the goal is to investigate how CD112R regulates anti- tumor immune response in vivo. In the following aims, I propose to utilize genetic knockout mice in addition to generating a monoclonal antibody directed against CD112R to: Aim 1: Investigate effect of loss of Pvrig in anti-tumor immunity. Using Pvrig knockout mice, I will investigate changes in myeloid cells and T cells in the tumor microenvironment, using the MC38 colon carcinoma model. Aim 2: Generate anti-CD112R monoclonal antibodies. We will immunize Pvrig knock- out mice with Pvrig cDNA with the aim to generate aCD112R agonistic antibody to ameliorate autoimmune inflammation and blocking antibodies to promote anti-tumor immunity. Together these novel tools will enable the characterization of the expression and regulation of CD112R during anti-tumor immunity and autoimmune inflammation in the future.