Hungarian Immunology

[Regional cues and phenotypic responses during the ontogeny and postnatal development of splenic vasculatur]

BALOGH Péter

JANUARY 30, 2006

Hungarian Immunology - 2006;5(01)

[Among structured peripheral lymphoid tissues in man and rodents, the spleen demonstrates the most extensive flexibility in functional activities, which is coupled with considerable tissue architecture adjustments during ontogeny and immune reactions. The sequential conversion of a primary lymphohemopoietic tissue into a major peripheral lymphoid organ (while participating in the post-myeloid period of primary B-lymphopoiesis and retaining the potential for myelopoiesis) is accompanied with the ordered segregation involving various non-hemopoietic components of architecture, including the endothelia of blood vessels. In this report we will survey the functional and structural aspects of heterogeneous endothelial cells lining the various splenic vascular beds, comprising the complex circulatory network of the spleen. These features will be correlated with the characteristics of those regulatory mechanisms that have recently been demonstrated to be responsible for the establishment and maintenance of the endothelial divergence during splenic vascular development, including crucial transcription factors, morphogenic regulatory ligands and receptors of the tumor necrosis factor/lymphotoxin (TNF/LT) family and others. The influence of these regulatory elements in mice appears to be highly restricted in terms of regional involvement of the vasculature, with cellular alterations of the marginal sinus representing the most frequently affected region. This complexity highlights the importance of this tissue region in both the formation of splenic vasculature and a possible source for white pulp stromal elements as well as its function as a major gateway for lymphocyte traffic.]

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