Age-dependent susceptibility to a viral disease due to decreased natural killer cell numbers and trafficking

Area of Science:

• Immunology
• Virology
• Gerontology

Background:

• Aged individuals exhibit heightened susceptibility to viral infections compared to younger populations.
• Specific immune system dysfunctions underlying this age-related vulnerability remain largely unidentified.
• Mousepox serves as a relevant model for studying human smallpox and age-related disease resistance.

Purpose of the Study:

• To identify the specific immune system defects responsible for increased susceptibility to viral diseases in aged hosts.
• To investigate the role of T cell responses and natural killer (NK) cells in age-dependent loss of resistance to mousepox.
• To explore potential therapeutic strategies targeting NK cell function to enhance resistance in aging populations.

Main Methods:

• Utilized genetically resistant mice to mousepox, assessing resistance changes with age.
• Evaluated T cell responses in mid-aged mice exhibiting loss of resistance.
• Quantified total and mature natural killer (NK) cell populations and assessed their migratory capacity to lymph nodes in aged mice.

Main Results:

• Mice genetically resistant to mousepox lost resistance at mid-age.
• The loss of resistance was not attributed to intrinsic defects in T cell responses.
• A significant decrease in the number and impaired migration of natural killer (NK) cells to lymph nodes was observed in aged mice.

Conclusions:

• Age-dependent susceptibility to viral diseases is linked to specific defects in natural killer (NK) cell number and function.
• Impaired NK cell migration to lymph nodes is a primary reason for reduced resistance to systemic viral spread in aged hosts.
• Targeting NK cell function presents a potential therapeutic avenue for improving viral disease resistance in the elderly.