NKp80 defines and stimulates a reactive subset of CD8 T cells

Area of Science:

• Immunology
• Cell Biology

Background:

• NKp80 is an activating C-type lectin-like receptor (CTLR) primarily on natural killer (NK) cells, crucial for cytotoxicity and cytokine release.
• The ligand for NKp80 is activation-induced C-type lectin (AICL), a myeloid-specific CTLR encoded within the natural killer gene complex (NKC).

Purpose of the Study:

• To investigate the expression and function of NKp80 on human CD8 T cells.
• To determine if NKp80 influences CD8 T cell responses, particularly in inflammatory contexts.

Main Methods:

• Gene expression profiling and flow cytometry to analyze NKp80 expression on T cells.
• Functional assays measuring degranulation and cytokine secretion (IFN-gamma) upon NKp80 ligation.
• Studies involving AICL-expressing cells and macrophages to assess CD8 T cell activation.

Main Results:

• NKp80 is expressed on a subset of human CD8 T cells with an effector memory phenotype and high responsiveness.
• This NKp80(+) T cell subset coexpresses NK receptors and elevated cytotoxic/adhesion molecules.
• NKp80 ligation enhances CD3-stimulated degranulation and IFN-gamma secretion by effector memory T cells.
• Engagement of NKp80 by AICL-expressing cells or macrophages significantly boosts CD8 T cell responses in alloreactive settings.

Conclusions:

• NKp80 is present on a responsive subset of effector memory CD8 T cells, conferring an NK-like inflammatory phenotype.
• NKp80 promotes CD8 T cell responses against AICL-expressing cells, including myeloid cells.
• NKp80 may mediate functional interactions between effector memory CD8 T cells and myeloid cells at sites of inflammation.