Theranostics 2020; 10(10):4481-4489. doi:10.7150/thno.41646

Research Paper

Human CD8 T cells are susceptible to TNF-mediated activation-induced cell death

Itziar Otano1,2✉, Maite Alvarez1,2, Luna Minute1,2, María Carmen Ochoa1,2,3,7, Itziar Migueliz2,7, Carmen Molina1,2, Arantza Azpilikueta1,2, Carlos E. de Andrea2,3,4,5, Iñaki Etxeberria1,2, Miguel F. Sanmamed1,2,6, Álvaro Teijeira1,2,3, Pedro Berraondo1,2,3*, Ignacio Melero1,2,3,6,7*✉

1. Program of Immunology and Immunotherapy, Cima Universidad de Navarra, Pamplona, Spain.
2. Navarra Institute for Health Research (IDISNA), Pamplona, Spain.
3. Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain.
4. Department of Pathology, Clínica Universidad de Navarra, Pamplona, Spain.
5. Department of Histology and Pathology, Universidad de Navarra, Pamplona, Spain.
6. Department of Oncology, Clínica Universidad de Navarra, Pamplona, Spain.
7. Department of Immunology and Immunotherapy, Clínica Universidad de Navarra, Pamplona, Spain.
*Senior co-authors.

This is an open access article distributed under the terms of the Creative Commons Attribution License ( See for full terms and conditions.
Otano I, Alvarez M, Minute L, Ochoa MC, Migueliz I, Molina C, Azpilikueta A, de Andrea CE, Etxeberria I, Sanmamed MF, Teijeira Á, Berraondo P, Melero I. Human CD8 T cells are susceptible to TNF-mediated activation-induced cell death. Theranostics 2020; 10(10):4481-4489. doi:10.7150/thno.41646. Available from

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Activation-induced cell death (AICD) is a complex immunoregulatory mechanism that causes the demise of a fraction of T-lymphocytes upon antigen-driven activation. In the present study we investigated the direct role of TNF in AICD of CD8 T lymphocytes.

Methods: Human peripheral mononuclear cells were isolated from healthy donors and fresh tumor-infiltrating lymphocytes were obtained from cancer patients undergoing surgery. T cells were activated with anti-CD3/CD28 mAbs or with a pool of virus peptides, in combination with clinical-grade TNF blocking agents.

Results: A portion of CD8 T cells undergoes apoptosis upon CD3/CD28 activation in a manner that is partially prevented by the clinically used anti-TNF agents infliximab and etanercept. TNF-mediated AICD was also observed upon activation of virus-specific CD8 T cells and tumor-infiltrating CD8 T lymphocytes. The mechanism of TNF-driven T cell death involves TNFR2 and production of mitochondrial oxygen free radicals which damage DNA.

Conclusion: The use of TNF blocking agents reduces oxidative stress, hyperpolarization of mitochondria, and the generation of DNA damage in CD8 T celss undergoing activation. The fact that TNF mediates AICD in human tumor-reactive CD8 T cells suggests that the use of TNF-blocking agents can be exploited in immunotherapy strategies.

Keywords: TNF, AICD, mitochondria hyperpolarization, DNA damage