T cell-derived tumor necrosis factor induces cytotoxicity by activating RIPK1-dependent target cell death

Area of Science:

• Immunology
• Cellular Biology
• Molecular Biology

Background:

• Tumor necrosis factor (TNF) binding to TNF receptor 1 (TNFR1) can initiate either inflammation and cell survival or programmed cell death pathways like apoptosis and necroptosis.
• The specific cellular origin of TNF that triggers RIPK1-dependent cell death has been an unresolved question in the field.

Purpose of the Study:

• To investigate the cellular source of TNF responsible for RIPK1-dependent cell death.
• To determine the role of T cell-derived TNF in mediating target cell cytolysis and its implications in immune responses.

Main Methods:

• Utilized in vitro systems and murine models of T cell-mediated transplant and tumor rejection.
• Genetically modified target cell susceptibility to RIPK1-dependent cell death.

Main Results:

• Demonstrated that TNF released by T cells is essential and sufficient to activate RIPK1-dependent cell death in target cells.
• Showed that T cell-derived TNF mediates target cell lysis independently of T cell numbers.
• Confirmed that this pathway accelerates cardiac allograft rejection in mice.
• Revealed synergy between T cell TNF and anti-PD1 therapy in overcoming resistance in murine melanoma models.

Conclusions:

• Identified a novel immunological function for TNF secreted by cytotoxic effector T cells upon engagement with their targets.
• Proposed that modulating T cell TNF production or target cell sensitivity to RIPK1-dependent cell death can be leveraged to enhance or reduce T cell-mediated destruction of allografts and tumors.
• Highlighted potential therapeutic strategies for improving outcomes in transplantation and cancer immunotherapy.