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Phenotypic characteristics and significance of reticular meshwork surrounding splenic white pulp of mice
1Division of Molecular Cell Biology, Jikei University School of Medicine, Tokyo, Japan.
Abstract:
This report describes the phenotypic characteristics of the reticular meshwork (RM) localized between the marginal zone and white pulp of mice. Considered from an anatomical point of view, RM contributes to the migration of lymphocytes into splenic white pulp. We divided the RM into two parts: one surrounding the periarterial lymphoid sheaths (PALS) and the other surrounding the follicles. Throughout both locations of RM, alkaline phosphatase activity was noted on the plasma membrane of the reticular cells and tenascin was expressed on the collagen fibrils in the matrix of the reticular fibers. In contrast, the expression of MAdCAM-1, one of the homing receptors of lymphocytes, was solely confined to the plasma membranes of the fiber-forming reticular cells and processes of the perifollicular RM. In aly mice with defective perifollicular RM and loss of MAdCAM-1 expression, lymphocyte homing to the white pulp was remarkably inhibited, and the compartmentalization of T and B cells did not occur. This fact supports the notion that perifollicular RM plays an essential role in lymphocyte homing and compartmentalization.
Insights
The reticular meshwork (RM) in mouse spleens is crucial for lymphocyte migration. Defective perifollicular RM impairs lymphocyte homing and cell compartmentalization, highlighting its essential role.
Area of Science:
- Immunology
- Cell Biology
- Anatomy
Background:
- The reticular meshwork (RM) in the spleen plays a role in lymphocyte migration.
- Understanding the specific functions of different RM regions is important for immunology.
Purpose of the Study:
- To characterize the phenotypic features of the reticular meshwork (RM) in mice.
- To investigate the role of the perifollicular RM in lymphocyte homing and compartmentalization.
Main Methods:
- Phenotypic analysis of RM in mouse spleens.
- Immunohistochemistry to detect specific molecular markers.
- Comparative study of wild-type and aly mice with defective RM.
Main Results:
- The RM exhibits distinct characteristics in different splenic locations.
- Alkaline phosphatase and tenascin are present throughout the RM.
- MAdCAM-1 expression is restricted to the perifollicular RM.
- Mice with defective perifollicular RM show inhibited lymphocyte homing and T/B cell compartmentalization.
Conclusions:
- The perifollicular RM is essential for lymphocyte homing to the splenic white pulp.
- MAdCAM-1 expression in the perifollicular RM is critical for lymphocyte trafficking and immune cell organization.