Page 72 - Veterinary Immunology, 10th Edition

VetBooks.ir Sentinel Cells

The cells whose primary function it is to recognize and respond to
invading microbes are called sentinel cells. The major sentinel cell

types, namely macrophages, dendritic cells, and mast cells, are
scattered throughout the body but are found in highest numbers
just below body surfaces, where invading microorganisms are most
likely to be encountered. All these cells are equipped with multiple,
diverse PRRs, so they can detect and then respond rapidly to both

PAMPs and DAMPs. Other cells scattered throughout the body,
such as epithelial cells, endothelial cells, neutrophils, and
fibroblasts, may serve as sentinel cells when opportunity arises.

Macrophages

The most important sentinel cells are macrophages. Macrophages
scattered throughout the body can capture, kill, and destroy
microbial invaders. Macrophages are described in detail in Chapter

6.

Dendritic Cells

The second major population of sentinel cells consists of dendritic

cells, so called because many possess long, thin cytoplasmic
processes called dendrites that can trap invaders. Dendritic cells
encompass several distinct cell types, many of which are closely
related to, or derived from, macrophages. They are discussed in
detail in Chapter 10.

Mast Cells

A third population of professional sentinel cells are the mast cells.
These cells, strategically located close to epithelial and endothelial

surfaces, are among the first to detect pathogens and danger
signals. They express multiple PRRs and are packed with granules
that store a complex mixture of inflammatory mediators. When
released in response to appropriate stimuli, these mediators

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