The PD-1/PD-L1 Pathway: A Perspective on Comparative Immuno-Oncology

Area of Science:

• Immunology
• Pathology
• Comparative Medicine

Background:

• The PD-1/PD-L1 pathway, known for its role in immuno-oncology and immune checkpoint therapy, also governs fundamental tissue physiology and homeostasis.
• This pathway is implicated in the pathogenesis of chronic infections, autoimmune diseases, and cancer.
• It serves as a key model for comparative pathology and the "one health one medicine" concept.

Purpose of the Study:

• To review novel research on the multifaceted PD-1/PD-L1 pathway.
• To elucidate its homeostatic role in a tissue-specific context.
• To explore translational research from mouse models to diverse animal species.

Main Methods:

• Review of early translational research using mouse models.
• Analysis of recent studies investigating the PD-1/PD-L1 pathway in multiple animal species.
• Comparative analysis of the pathway across species.

Main Results:

• The PD-1/PD-L1 pathway mediates essential immune tolerance and tissue homeostasis.
• Research extends beyond oncology to chronic infectious diseases, autoimmunity, and general pathology.
• Comparative studies reveal conserved and divergent roles of the PD-1/PD-L1 pathway across species.

Conclusions:

• The PD-1/PD-L1 pathway has broad physiological and pathological significance.
• Understanding its tissue-specific homeostatic functions is critical.
• Comparative pathology and One Health approaches are vital for translating findings between humans and animals.