The characterization of lymphocytes migrating through chronically inflamed tissues

Area of Science:

• Immunology
• Cell Biology
• Physiology

Background:

• Previous studies showed radiolabeled cells from lymphatics migrate back into lymph.
• Afferent lymph cells from granulomas showed preferential migration from blood into lymph.

Purpose of the Study:

• To identify the specific cell type responsible for preferential migration into lymphatics.
• To determine if inflammation or antigen presence drives this lymphocyte migration.

Main Methods:

• Cannulation of afferent lymphatics in granulomas and efferent lymphatics in lymph nodes of sheep.
• Intravenous administration of radiolabeled (111In) lymph cells.
• Analysis of cell migration patterns from blood into lymphatics and tissues.

Main Results:

• Small recirculating T lymphocytes were identified as the primary cells responsible for selective migration.
• Macrophages, lymphoblasts, and B cells did not exhibit this preferential migration.
• Lymphocyte migration occurred similarly in normal, uninflamed skin as in granulomas, indicating independence from inflammation or antigen.

Conclusions:

• Small T lymphocytes possess a unique migratory capacity from the bloodstream into lymphatic vessels.
• This migration is a characteristic of normal lymphocyte trafficking and not solely an inflammatory response.
• The findings suggest a fundamental mechanism for lymphocyte recirculation independent of specific antigenic or inflammatory cues.