Page 382 - Veterinary Immunology, 10th Edition

The emigration of lymphocytes from the bloodstream into tissues is
VetBooks.ir regulated by P-selectin (CD62P), L-selectin (CD62L), and E-selectin

(CD62E). P- and E-selectins are found on vascular endothelial cells.
When these cells are activated by inflammation, they express
selectins that bind neutrophils, activated T cells, and monocytes. L-

selectin binds lymphocytes to high endothelial venules in lymphoid
organs (Chapter 12).

Immunoglobulin Superfamily
Some members of the immunoglobulin superfamily (IgSF) are

lymphocyte adhesion molecules. For example, ICAM-1 (CD54)
binds to the integrin, CD11a/CD18 (see Fig. 13.9). ICAM-1 is
normally expressed on dendritic cells and B cells. Inflammation

induces ICAM-1 expression on vascular endothelium and permits
phagocytic cells to bind and move into inflamed tissues. ICAM-1 is
also responsible for the migration of T cells into areas of
inflammation (so-called delayed hypersensitivity reactions; Chapter
33). Another IgSF adherence molecule is vascular cell adhesion

molecule-1 (VCAM-1), or CD106. VCAM-1 is expressed on
inflamed vascular endothelial cells. It binds the β -integrin,
1
CD49d/CD29, on lymphocytes and monocytes. (The essential
antigen-binding receptors on lymphocytes are also members of the
IgSF [see Fig. 14.1].)

CD58 and CD2

CD58 is the ligand for CD2. CD2 is found only on T cells, whereas
CD58 is widely distributed on many cell types. When cytotoxic T
cells encounter their target cells, the T cell binds them through CD2

and CD58. It is likely that CD58 facilitates T cell binding to any cell
undergoing surveillance (Chapter 18). CD58 is found on antigen-
presenting cells such as dendritic cells and macrophages. When it
binds to T cell CD2, CD58 enhances the recognition of antigen by
the T cell and at the same time stimulates the antigen-presenting

cell to secrete cytokines.

Other Major Surface Molecules

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