Page 630 - Veterinary Immunology, 10th Edition

Interleukin-10
VetBooks.ir IL-10 is a cytokine that inhibits both innate and adaptive immune

responses (see Fig. 20.12). It is produced by macrophages
(especially M2 macrophages) and classical dendritic cells in
response to microbial products. It is also produced by multiple T

cell subsets, including some populations of helper T cells in
response to high antigen doses and IL-12. It is produced in
especially large amounts by Treg cells in response to TGF-β. Small
amounts of IL-10 may also be produced by B cells, mast cells,
neutrophils, and natural killer (NK) cells.

IL-10 down-regulates MHC class II and co-stimulatory molecule
expression on dendritic cells and macrophages and hence impairs
antigen presentation. IL-10 or IL-10-treated dendritic cells can

induce a long-lasting, antigen-specific, anergy in T cells. IL-10
inhibits the synthesis of the Th1 cytokines, IL-1, IFN-γ, and TNF-α,
and the Th2 cytokines IL-4 and IL-5. Thus it can regulate both Th1
and Th2 responses. IL-10 also inhibits the production of IL-5,
CXCL8, IL-12, granulocyte-macrophage colony-stimulating factor

(GM-CSF), and granulocyte colony-stimulating factor (G-CSF). It
down-regulates the production of IFN-γ and TNF-α by NK cells.

Transforming Growth Factor-β

TGF-β comprises a family of five glycoproteins; three (TGF-β1,

TGF-β2, and TGF-β3) are found in mammals, and two others (TGF-
β4 and TGF-β5) have been described in chickens and Xenopus toads.
They are secreted as inactive precursors that are activated on the
cell surface by proteases after binding to integrins. TGFs are

produced by platelets, activated macrophages, neutrophils, B cells,
and T cells and act on T and B cells, dendritic cells, macrophages,
neutrophils, and fibroblasts (Fig. 20.13).

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