Thursday, March 20, 2025
3/20/2025
Summary T cells play a central role in the adaptive immune system and are activated in response to T cell receptor (TCR) recognition of antigen loaded on the major-histocompatibility complex (MHC) of antigen presenting cells (APCs). In order to fully achieve T cell effector function, an essential “second signal” is provided by engagement of the T cell costimulatory receptor CD28 with its B7 ligands (CD80/CD86) on the APC. We recently demonstrated that sialic acids on T cells and APCs dampen CD28 binding to CD80/CD86 and that removal of sialic acids with sialidase enhances T cell proliferation. Sialic acid removal is also synergistic with programmed cell death protein-1 (αPD1) checkpoint inhibitor blockade for functional revival of exhausted T cells. In this project, we will develop bifunctional αPD1-sialidase conjugates that are expected to combine the benefits of PD1 blockade with removal of sialic acid ligands of CD28 to promote engagement with B7 ligands and enhance T cell activation. We will evaluate these reagents in animal models of cancer for their therapeutic potential to invigorate exhausted T cells and suppress cancer progression.
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