File:Spleen structure 01.jpg: Difference between revisions

• The white pulp consists of T cell (lymphocyte) zones (also known as the periarteriolar lymphoid sheath (PALS)) containing networks of fibroblastic reticular cells (FRC) surrounding a central arteriole, together with B cell follicles containing a central network of follicular dendritic cells (FDC).
• Marginal zones (MZ) surrounding the white pulp contain marginal reticular cells (MRC), particularly at the edges of the B cell follicles.
• Blood and leukocytes entering the spleen pass through branches of the central arteriole, which end in the marginal sinuses and red pulp.
• In the cords of the red pulp, a dense network of reticular fibroblasts and fibres construct an open blood network, which is marked by its lack of a typical endothelial cell lining.
• Large numbers of macrophages phagocytose dying or damaged red blood cells in the red pulp (not shown).
• Immune cells enter the white pulp at regions where the T cell zones abut the MZ, known as the MZ bridging channels.

• The distribution of cells:
  • T cells - (white) CD3+
  • B cells - (blue) B220+
  • macrophages - (cyan) CD169+ MZ
  • dendritic cells - (green) (DCs) CD11c+
  • stromal cells - (red) ER-TR7+

• The distinct organization of stromal cells in different regions of the spleen is shown by single-colour immunofluoresence staining (right panel).
• Networks of stromal cells and reticular fibres form in the white pulp, including the fibroblastic reticular cells (FRCs) in T cell zones, follicular dendritic cells (FDCs) in B cell follicles (ER-TR7−) and marginal reticular cells (MRCs) in the MZ.
• A dense network of stromal cells and reticular fibres is present in the red pulp.

Scale bars represent 130 μM.