Spatial Memory Performance Associated with Measures of Immune Function in Elderly Female Rhesus Macaques

Area of Science:

• Immunology
• Neuroscience
• Gerontology

Background:

• Aging is associated with cognitive decline and altered immune function.
• Previous research linked spatial memory in aged female rhesus macaques to sleep patterns and M1 receptor binding.

Purpose of the Study:

• To investigate the correlation between spatial memory and adaptive immune responses to vaccination in aged female rhesus macaques.

Main Methods:

• Aged female rhesus macaques were classified as good spatial performers (GSP) or poor spatial performers (PSP) based on maze performance.
• The adaptive immune response to vaccination was assessed by measuring CD4 and CD8 T cell responses (interferon-gamma production) and antibody titers.

Main Results:

• GSP group showed a higher frequency of CD8 interferon-γ (IFN-γ) producing cells post-vaccination compared to the PSP group.
• CD8 IFN-γ positive cell counts correlated with better sleep quality.
• The PSP group exhibited a significantly higher antibody titer than the GSP group, which negatively correlated with daytime activity.

Conclusions:

• Superior spatial memory in aged female macaques is associated with a more robust CD8 T cell-mediated immune response.
• Conversely, better cognitive performance correlates with a reduced antibody response to vaccination.
• These findings highlight a dissociation between cellular and humoral immune responses in relation to cognitive function in aging.