Multi-color flow cytometry for evaluating age-related changes in memory lymphocyte subsets in dogs

Area of Science:

• Immunology
• Comparative Medicine
• Gerontology

Background:

• Dogs are valuable large-animal models for studying human diseases.
• Age-related immune decline (immunosenescence) in dogs is poorly understood due to undefined T lymphocyte phenotypes.
• Characterizing canine immune cells is crucial for accurate disease modeling.

Purpose of the Study:

• To define naïve and memory T lymphocyte subsets in dogs using multi-color flow cytometry.
• To evaluate age-related changes in T lymphocyte populations and function in beagles.
• To compare canine immunosenescence to findings in other species.

Main Methods:

• Multi-color flow cytometry was used on peripheral blood mononuclear cells from young and aged beagles.
• Antibodies targeting CD45RA, CD62L, CD28, and CD44 were employed to identify T lymphocyte subsets.
• Cytokine production and proliferative capacity of T lymphocyte subsets were assessed.

Main Results:

• Antibodies targeting CD45RA and CD62L effectively defined canine naïve, central memory, effector memory, and terminal effector T lymphocyte subsets.
• Aged dogs exhibited decreased frequencies of naïve-like CD4+ and CD8+ T lymphocytes.
• Older dogs showed an increased frequency of terminal effector-like CD8+ T lymphocytes, with altered cytokine production and reduced proliferative capacity.

Conclusions:

• The study successfully defined canine T lymphocyte subsets crucial for studying immunosenescence.
• Aged dogs display distinct immunological features mirroring age-related immune decline observed in other species.
• These findings enhance the utility of dogs as models for age-related diseases.