Chronic CD27-CD70 costimulation promotes type 1-specific polarization of effector Tregs

Area of Science:

• Immunology
• T cell biology
• Costimulatory receptors

Background:

• Most T lymphocytes, including regulatory T cells (Tregs), express the CD27 costimulatory receptor.
• CD27 engagement on conventional T cells promotes Th1 and cytotoxic responses.
• The effect of CD27 engagement on the regulatory T cell lineage remains largely unknown.

Purpose of the Study:

• To investigate the impact of constitutive CD27 engagement on both regulatory and conventional CD4+ T cells in vivo.
• To elucidate the role of CD27 in T cell polarization and immune response development.

Main Methods:

• Studied CD4+ T cells (conventional and regulatory) in vivo.
• Examined the effects of constitutive CD27 engagement without intentional antigenic stimulation.
• Utilized transfer experiments to assess Treg activation.

Main Results:

• Both conventional T cells (Tconvs) and Tregs polarized into type 1 subsets.
• Activated T cells exhibited increased cytokine production and IFN-γ responsiveness.
• Cells showed CXCR3-dependent migration to inflammatory sites.
• CD27 engagement was found to trigger Treg activation in a cell-autonomous manner.

Conclusions:

• CD27 engagement drives T cell polarization towards type 1 responses.
• CD27 signaling influences Treg activation and function.
• CD27 may regulate Th1 immunity development in peripheral tissues.
• CD27 signaling could impact the transition of effector responses to long-term memory.