Granulocyte and natural killer activity in the elderly

Area of Science:

• Immunology
• Gerontology
• Cellular Biology

Background:

• Ageing leads to immunosenescence, a decline in immune system function.
• This decline is linked to increased susceptibility to infections, autoimmune diseases, and cancer.
• While T-cell changes are known, the impact on non-specific immunity requires further investigation.

Purpose of the Study:

• To investigate age-related changes in neutrophil (PMN) function, including superoxide production, chemotaxis, and apoptosis.
• To assess age-related differences in basal natural killer (NK) cell activity and CD16+ cell numbers.
• To determine the role of these innate immune changes in the overall process of immunosenescence.

Main Methods:

• Assessed superoxide production and chemotaxis in neutrophils from young and elderly subjects.
• Measured APO1/Fas (CD95) expression on neutrophils to evaluate apoptosis.
• Quantified basal NK activity and the number of CD16+ cells in young and elderly individuals.

Main Results:

• Significant age-related decreases in neutrophil superoxide production and chemotaxis were observed.
• No significant correlation was found between age and CD95 expression on neutrophils.
• A significant age-related decrease in NK cell activity was noted, despite an increased number of CD16+ cells in the elderly.

Conclusions:

• Immunosenescence involves a decline in non-specific immunity, including impaired neutrophil function and reduced NK cell activity.
• Decreased neutrophil function is not primarily driven by CD95-mediated apoptosis.
• The findings highlight deficits in innate immunity as a significant factor in the pathogenesis of immunosenescence.