T-Cell Exhaustion Assay

Background: T-cell exhaustion can occur during chronic infection and cancer due to the persistence of antigen and inflammation in local tissues.  When T-cells are repeatedly stimulated, negative feedback loops limit inflammation, an event known as T-cell exhaustion. These tolerogenic feedback loops are required for normal, healthy function of T-cell activation; preventing T-cells from becoming overstimulated and damaging healthy tissues (e.g. auto-immune disorders). Blockade of immune checkpoint receptors, such as the PD-1/PD-L1 pathway, can ameliorate or partially reverse T-cell exhaustion and improve immune responses. These assays can also be utilized to explore the efficacy of new checkpoint drug candidates in development.

Principle: In this assay, lymphocytes (PBMCs) are stimulated for several days to exhaust T-cells. The cells are then re-stimulated in the presence of a checkpoint inhibitor or other immunomodulatory article to observe if T-cell exhaustion can be rerouted. Lymphocyte response (proliferation, activation, cytokines, etc.) are measured to assess the effect caused by therapeutic intervention.

References:

1. Dunsford, L. S., Thoirs, R. H., Rathbone, E. & Patakas, A. A Human In Vitro T Cell Exhaustion Model for Assessing Immuno-Oncology Therapies. in Immuno-Oncology: Cellular and Translational Approaches (ed. Tan, S.-L.) 89–101 (Springer US, 2020). doi:10.1007/978-1-0716-0171-6_6.
2. Wherry, E. J. & Kurachi, M. Molecular and cellular insights into T cell exhaustion. Nat. Rev. Immunol. 15, 486–499 (2015).

 Related Assays:

There are many variations on Checkpoint inhibitor (CI) assays, where the method of T-cell activation and CI addition differs with immunological mechanism of interest:

• T-cell Activation/Checkpoint Inhibitor Assay
• Recall Antigen Assay
• Antigen Specific T-cell activation Assay
• T-Reg Suppression Assay
• Tumor cytotoxicity Assay
• Patient Screening for exhausted T-cells