Page 381 - Veterinary Immunology, 10th Edition

Adherence Molecules
VetBooks.ir As discussed in Chapter 2, some cell surface molecules bind cells

together. They regulate signal network transmission between the

cells of the immune system and control the movement of leukocytes
in tissues. The cell adhesion molecules found on lymphocytes
include integrins, selectins, and members of the immunoglobulin
superfamily.

Integrins

Integrins are heterodimeric proteins formed by α and β chains. The
β -integrins consist of a β chain (CD29) paired with one of several
1 1
different α chains (CD49). They bind cells to extracellular matrix
proteins such as fibronectin, laminin, and collagen. The β -integrins
2
consist of a β chain (CD18) paired with one of several α chains
2
(CD11). They control the binding of leukocytes to vascular
endothelium and bind T cells to antigen-presenting cells. For

example, LFA-1 (CD11a/CD18) on a T cell binds to its ligand,
intercellular adhesion molecule-1 (ICAM-1), on the antigen-
presenting cell. By prolonging and stabilizing cell interactions, this
binding permits successful antigen recognition (Fig. 13.9).

FIG. 13.9 The β -integrins act as cell surface adhesion molecules
2
to link cells together so that they can communicate privately. The
integrins consist of families of paired peptide chains (heterodimers).
These families are based on pairing many different α chains with a
limited number of β chains.

Selectins

381