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Summary
Intravenous inoculation of rats with dextran sulfate or polymethacrylic acid inhibits lymphocyte passage through high endothelial venules (HEC). This study reveals a novel mechanism affecting immune cell trafficking in lymph nodes.
Area of Science:
- Immunology
- Cell Biology
- Histology
Background:
- Lymphocyte homing is crucial for immune surveillance.
- High endothelial venules (HEV) are key sites for lymphocyte entry into lymph nodes.
- The mechanisms regulating lymphocyte transmigration are not fully understood.
Purpose of the Study:
- To investigate the effect of dextran sulfate and polymethacrylic acid on lymphocyte passage through HEV.
- To elucidate the cellular and ultrastructural changes in lymph nodes following inoculation.
Main Methods:
- Intravenous inoculation of rats with dextran sulfate or polymethacrylic acid.
- Electron microscopy of rat cervical lymph node sections.
- Comparative analysis of HEV morphology and lymphocyte interaction in control and treated rats.
Main Results:
- Inoculation induced lymphocytosis.
- Control rats showed active lymphocyte passage through HEV.
- Treated rats exhibited blocked lymphocyte transmigration, with lymphocytes apposed to HEV luminal walls but not passing through.
Conclusions:
- Dextran sulfate and polymethacrylic acid interfere with lymphocyte extravasation.
- HEV function is impaired, preventing lymphocyte entry into lymph nodes.
- This suggests a potential mechanism for modulating immune responses by altering lymphocyte trafficking.