Canine memory T-cell subsets in health and disease

Area of Science:

• Immunology
• Veterinary Medicine
• Comparative Immunology

Background:

• Understanding canine T-lymphocyte immunity is vital for advancing diagnostics, therapeutics, and using dogs in comparative immunology research.
• Characterizing T-cell subsets, including naïve (TN), central memory (CM), effector memory (EM), and terminal effector memory re-expressing CD45RA (TEMRA), is essential for assessing immune status.

Purpose of the Study:

• To quantify canine memory T-cell subsets in healthy dogs and those with dermatologic inflammation, solid tumors, or lymphoma.
• To investigate the utility of CD45RA and CD62L markers in defining T-cell subsets for clinical immunology studies in dogs.

Main Methods:

• Peripheral blood mononuclear cells (PBMCs) were collected from dogs with dermatologic inflammation (n=9), solid tumors (n=9), lymphoma (n=9), and healthy controls (n=15).
• Flow cytometry was used to define T-cell subsets (CD4+, CD8+, TN, CM, EM, TEMRA) based on CD45RA and CD62L expression.
• Statistical analysis (Mann-Whitney test) compared T-cell subset proportions between disease groups and controls.

Main Results:

• Dogs with dermatologic inflammation showed significantly increased CD8+ TN and decreased CD8+ TEMRA cells compared to healthy controls (P=0.036 and P=0.045, respectively).
• A positive correlation was observed between CD4+ TN cells and the Canine Atopic Dermatitis Extent and Severity Index (CADESI) score in the inflammation group (ρ=0.817, P=0.011).
• No significant differences in T-cell subsets were found between cancer groups (solid tumors, lymphoma) and healthy controls.

Conclusions:

• Dermatologic inflammation in dogs alters peripheral blood T-cell subset proportions, potentially due to T-cell migration into affected tissues.
• The markers CD45RA and CD62L are valuable tools for characterizing canine immune responses in clinical settings.
• Further research into canine T-cell subsets can improve immunotherapeutic strategies and the use of dogs as models for human diseases.