Human Adaptive Natural Killer Cells: Beyond NKG2C

Area of Science:

• Immunology
• Virology
• Cell Biology

Background:

• Adaptive natural killer (NK) cells, characterized by NKG2C expression, are known to develop in individuals with human cytomegalovirus (HCMV) infection.
• The precise mechanisms and alternative pathways for adaptive NK cell generation remain incompletely understood.

Purpose of the Study:

• To investigate the generation of adaptive NK cells in individuals lacking the NKG2C receptor but infected with HCMV.
• To identify novel co-stimulatory receptors involved in the function of adaptive NK cells.

Main Methods:

• Flow cytometry analysis of peripheral blood mononuclear cells.
• Genetic analysis to assess NKG2C receptor expression.
• Functional assays to evaluate NK cell responses.

Main Results:

• Individuals with NKG2C deficiency (NKG2C-/-) and HCMV infection were found to generate adaptive NK cells.
• CD2 was identified as a crucial co-stimulatory receptor for these adaptive NK cells.
• These adaptive NK cells exhibit specialized responses mediated through FcγRIIIa/CD16.

Conclusions:

• Adaptive NK cell generation is not solely dependent on NKG2C expression.
• CD2 plays a significant role in the activation and function of adaptive NK cells in the context of HCMV infection.
• These findings expand our understanding of NK cell adaptability and immune responses to viral infections.