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Immunohistochemical study on leukocyte adhesion molecules expressed on lymphatic endothelium
1Hokkaido University School of Dentistry, Department of Oral Anatomy I, Prosthetics Dentistry I, N13 W7, Kita-ku, Sapporo, 060-8586, Japan.
Insights
Platelet-endothelial cell adhesion molecule-1 (PECAM-1) is strongly expressed on lymphatic endothelium in the human small intestine and lymph nodes. This molecule may aid lymphocyte adherence to lymphatic vessels, suggesting tissue-specific differences in adhesion molecule expression.
Area of Science:
- Immunology
- Vascular Biology
- Gastroenterology
Background:
- Lymphatic endothelium plays a crucial role in immune cell trafficking.
- Understanding leukocyte adhesion molecules is key to deciphering immune cell migration into lymphatic vessels.
Purpose of the Study:
- To investigate the expression patterns of key leukocyte adhesion molecules on lymphatic endothelium in the human small intestine and submandibular lymph node.
- To determine the potential role of these molecules in lymphocyte homing to lymphatic capillaries.
Main Methods:
- Immunohistochemical analysis was employed to detect adhesion molecule expression.
- Human small intestine and submandibular lymph node tissues were examined.
Main Results:
- Strong expression of platelet-endothelial cell adhesion molecule-1 (PECAM-1) was observed on lymphatic capillaries in both tissues.
- Intercellular adhesion molecule-1 (ICAM-1) and endothelial cell-selectin showed minimal or undetectable expression on lymphatic capillaries.
- Expression patterns varied between the small intestine and lymph node.
Conclusions:
- PECAM-1 is a prominent adhesion molecule on lymphatic endothelium, likely facilitating lymphocyte adherence.
- Lymphocyte migration into lymphatic capillaries may not necessitate multiple adhesion molecules.
- Adhesion molecule expression on lymphatic endothelium exhibits tissue-specific regulation.
Abstract:
Leukocyte adhesion molecules expressed on the lymphatic endothelium in human small intestine and submandibular lymph node were studied immunohistochemically. Lymphatic capillaries in the lamina propria, mucosal muscle layer, and submucosal connective tissue of the intestine and in the capsule of the lymph node showed strong expression of platelet-endothelial cell adhesion molecule-1 (PECAM-1). A few lymphatic capillaries that weakly expressed intercellular adhesion molecule-1 (ICAM-1) were found in the capsule of the lymph node but in the small intestine, no lymphatic capillaries expressed detectable amounts of ICAM-1. Lymphatic capillaries also did not express detectable amounts of endothelial cell-selectin in the small intestine and lymph node. When lymphocytes migrate from tissue into lymphatic capillaries, multiple adhesion molecules may not be required for the migration. PECAM-1, however, may contribute to adherence of lymphocytes to lymphatic endothelium and the expression of adhesion molecules on lymphatic endothelium may be different between tissues.