How do cancer cells bypass TCR-mediated T cell recognition?

As part of a larger series of mechanisms collectively termed “immune evasion”, cancer cells have developed several strategies to avoid T cell detection. One tactic is to express ligands such as PD-L1 and CD80 which bind to “immune checkpoint receptors” on the T cell. This interaction prevents T cell activation and/or promotes T cell deactivation.1 Alternatively, tumor cells may limit antigen presentation by downregulating MHC surface expression, or induce T cell anergy by interacting with the TCR in the absence of co-stimulation. Finally, cancer cells have been observed to directly cause T cell apoptosis.2 For an expanded view into CAR-T cells please visit our resource center.

1. J. Dine, et al., “Immune Checkpoint Inhibitors: An Innovation in Immunotherapy for the Treatment and Management of Patients with Cancer,” Asia Pac J Oncol Nurs 4(2):127-135, 2017.
2. D.S. Vinay, et al., “Immune evasion in cancer: Mechanistic basis and therapeutic strategies,” Semin Cancer Biol 35 Suppl:S185-S198, 2015.