Lymph node stromal cell

Beneath the external capsule and along the courses of the trabeculae, are peritrabecular and subcapsular sinuses.

These sinuses are cavities containing macrophages (specialised cells which help to keep the extracellular matrix in order).

[1] Naive lymphocytes (those with no history of contact with antigens) travel from the bone marrow or high endothelial venules of the thymus where they develop as lymphoblasts, to lymph nodes, where they mature.

Antigen-presenting cells accumulate near high endothelial venules to process soluble antigens.

[1] This type of receptor interacts with the chemokine CCL21, produced by fibroblastic reticular cells.

This means immune cells may leave the lymph node along a chemokine gradient.

Lymph node stromal cells express peripheral tissue-restricted antigens (PTAs) on their surface.

Most lymph node stromal cells preferentially express DF1, an Aire-like transcription modulator.

[1] Lymph node stromal cells can be grouped into six sub-populations, known by their expression of surface markers.

FRCs produce collagen alpha-1(III) rich reticular fibers that form a dense network within the lymphoid tissue.

FDCs assist the development of the germinal center via an interaction with B lymphocytes and helper T-lymphocytes.

[6] FDCs produce chemokine CXCL13 which promotes migration of B lymphocytes to the primary B cell follicle.

Via the reticular network, the MRCs bring antigens from the sub-capsular sinuses to the B cell follicles.

MRCs express the molecule TRANCE (also known as RANKL), a type of tumor necrosis factor.

They express adhesion molecules, chemokine CCL21, and lymphatic vessel endothelial hyaluronan receptor-1 (LYVE1), a homologue of CD44.

In the thymus, they line the high endothelial venules (HEVs) where lymphocytes originate.

[7] In mouse lymph nodes the HECs also express the chemokine CCL21 which will bind its receptor CCR7 on the naive T-cell and enhance the migration.