NK and NKT cell functions in immunosenescence

Area of Science:

• Immunology
• Gerontology
• Cellular Biology

Background:

• Immunosenescence, a decline in immune function, increases susceptibility to infections, cancer, and autoimmune diseases in aging organisms.
• While both innate and adaptive immune responses decrease with age, the body attempts to adapt to age-related deteriorations.
• Healthy centenarians may exhibit specific adaptive changes in their immune systems.

Purpose of the Study:

• To investigate the roles of Natural Killer (NK) and Natural Killer T (NKT) cells in immune responses during aging.
• To explore the preservation of innate and adaptive immune functions in very old age.
• To identify specific immune cell subsets, like NKT cells bearing TCR gammadelta, that may contribute to successful aging.

Main Methods:

• Comparative analysis of NK and NKT cell functions in aging populations.
• Assessment of cytotoxicity and interferon-gamma (IFN-gamma) production in NK and NKT cells.
• Evaluation of the impact of T-cell receptor (TCR) gammadelta expression on NKT cell activity.

Main Results:

• NK and NKT cell cytotoxicity and IFN-gamma production generally decrease with advancing age.
• In very old individuals, innate and adaptive immune responses appear preserved.
• NKT cells expressing TCR gammadelta exhibit enhanced cytotoxicity and IFN-gamma production in very old age.

Conclusions:

• NKT cells bearing TCR gammadelta may play a crucial role in maintaining immune function during aging, contributing to successful aging.
• The neuroendocrine-immune network and nutritional factors, like zinc, are important for preserving NK and NKT cell functions.
• Understanding these mechanisms can inform strategies to support immune health in the elderly.