CD4⁺ T cell immunity is dependent on an intrinsic stem-like program.

Area of Science:

• Immunology
• Transplantation Immunology
• Cellular Immunology

Background:

• CD4+ T cells are critical for immune responses, but the molecular mechanisms governing their long-term immunity are not fully understood.
• Understanding these mechanisms is vital for advancing T cell-based immunotherapies and managing transplant outcomes.

Purpose of the Study:

• To identify the molecular programs regulating CD4+ T cell immunity in transplantation models.
• To elucidate the mechanisms behind CD4+ T cell self-renewal and effector differentiation in the context of allograft rejection.

Main Methods:

• Single-cell transcriptomic analysis of CD4+ T cells in transplantation models.
• Adoptive transfer experiments to assess T cell function and allograft rejection.
• Genetic manipulation (deletion) of key transcription factors (IRF4) and enzymes (LDHA) in T cells.

Main Results:

• Naive CD4+ T cells differentiate into TCF1hi effector precursor (TEP) cells and TCF1-CXCR6+ effector cells.
• TCF1hi TEP cells possess self-renewal and differentiation potential, continuously supplying effector cells necessary for allograft rejection.
• IRF4 and LDHA are critical for effector differentiation; their deletion leads to transplant acceptance.

Conclusions:

• A stem-like program governed by TCF1, IRF4, and LDHA regulates CD4+ T cell self-renewal and effector function in transplantation.
• Targeting this program offers potential therapeutic strategies for modulating T cell responses in transplantation and immunotherapy.