CD39 is expressed on functional effector and tissue resident memory CD8+ T cells.

Area of Science:

• Immunology
• Cell Biology

Background:

• The ecto-enzyme CD39 (ATP-binding cassette subfamily D member 3) is known on exhausted CD8+ T cells during chronic viral infections.
• Its role in effector and memory T cell responses remains unclear, despite its proposed function as a marker for tumor-specific CD8+ T cells.

Approach:

• Investigated CD39 expression on effector CD8+ T cells, specifically short-lived effector cells (SLECs) and memory precursor effector cells (MPECs).
• Examined the impact of inhibiting CD39's enzymatic activity on MPEC differentiation and subsequent memory T cell formation in vivo.
• Analyzed CD39 and CD73 expression on tissue-resident memory (T_RM) cells in various tissues and in melanoma models.

Key Points:

• CD39 is expressed on SLECs, while its counterpart CD73 is on MPECs.
• Inhibiting CD39 activity in vitro boosts MPEC differentiation in vivo, leading to enhanced T_RM cell establishment in the brain and salivary gland after viral infection.
• CD39+ T_RM cells are functional, unlike their counterparts in chronic infections.

Conclusions:

• CD39's ATPase activity is crucial for effective memory CD8+ T cell differentiation.
• CD39 is present on functional T_RM cells in non-lymphoid tissues and melanoma, expanding its known roles beyond T cell exhaustion.