Lymph Drainage - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 180

Blood-convected pathogen antigens are trapped and processed in the marginal
zone by dendritic cells, macrophages, and marginal-zone B lymphocytes. In the B-
cell zone, antibody responses and germinal center reactions are initiated, whereas in
the T-cell zone, mature dendritic cells activate naive T lymphocytes. The territory of
B- and T-cell zones is determined by chemokines. Chemokine CXCL13 on the one
hand and CCL19 and CCL21 on the other form the B- and T-cell zones, respectively.
Chemokines CCL19 and CCL21 also contribute to macrophage positioning in the
marginal zone.

4.2.3 Other Secondary Lymphoid Tissues

Secondary lymphoid organs during embryonic and early postnatal period develop
owing to interaction of CD3 ) lymphoid-tissue inducer

cells with stromal lymphoid-tissue organizer cells . 8 Tumor-necrosis factor receptor
superfamily member TNFRSF3 9 of stromal lymphoid organizer cells interact
with the lymphokine and TNFRSF3 heterotrimeric ligand TNFSF2-TNFSF3 2 10 of
lymphoid-tissue inducer cells to organize the architecture of secondary lymphoid
organs and preserve their integrity.
The structure of secondary lymphoid organs maximizes the efficacy of immune
responses to viral infection. Later in life, structural integrity of secondary lymphoid
organs can be altered by infection, as antiviral cytotoxic T cells destroy stromal
cells of infected T-cell zone. Reacquisition of immune responsiveness requires
rebuilding of architecture of secondary lymphoid organs owing to crosstalk between
lymphoid-tissue inducer cells and stromal lymphoid-tissue organizer cells. Sec-
ondary lymphoid organs are repaired when lymphoid-tissue inducer cells proliferate
and accumulate in secondary lymphoid organs during peak infection and then
interact with fibroblastic reticular cells of the T-cell zone [ 323 ].
In adults, lymphoid-tissue inducer cells mainly contribute to the restoration
of the network of fibroblastic reticular cells . Fibroblastic reticular cells produce
chemokines involved in generating the T-cell zone of secondary lymphoid organs.
Therefore, restoration of the network of fibroblastic reticular cells allows chemokine
secretion after a transient loss. However, other cells in secondary lymphoid organs
can provide redundant cues for their restoration.
Lymphocytes B and T are sources of TNFSF2-TNFSF3 2 heterotrimers.
Consequently, reactivation of crosstalk between lymphoid-tissue inducer cells and
stromal lymphoid-tissue organizer cells is only mandatory when lymphoid organ
integrity is strongly impaired.

− ,CD4 + ,CD45 + (PTPRc +

8 CD3 accessory

receptor of the immunoglobulin superfamily is also called T-cell surface

glycoprotein T3. It forms CD3-TCR complex.
9 A.k.a. lymphotoxin-

receptor.
10 The TNFSF2-TNFSF3 2 heterotrimer, or lymphotoxin-

β

αβ 2 , is made of 2 lymphotoxin- β

subunit

α β

that anchor a lymphotoxin- (or TNF ) subunit to the cell surface.