Page 171 - Veterinary Immunology, 10th Edition

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FIG. 6.9 Some of the major surface receptors expressed by
macrophages and their functions.

CD64 is a high-affinity antibody receptor expressed on
macrophages and, to a lesser extent, on neutrophils. Like other
antibody receptors, CD64 binds the Fc region of antibody molecules
and thus is called an Fc receptor (FcγRI). Its expression is enhanced
by IFN-γ-induced activation so that a combination of antibody and

IFN-γ are potent macrophage activators. Human macrophages also
express two low-affinity antibody receptors, CD32 (FcγRII) and
CD16 (FcγRIII). Cattle and sheep macrophages express a unique Fc

receptor called Fcγ2R, which can bind particles coated with a
specific type of antibody called immunoglobulin G2 (IgG2)
(Chapter 16). Macrophages also have receptors for complement
components. These include CD35 (CR1) and CD11b/CD18, both of
which are C3b receptors.

Cell surface integrins bind macrophages to other cells, to
connective tissue molecules such as collagen and fibronectin, and to

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