Biomedical Engineering Reference
In-Depth Information
epithelial, endothelial, smooth muscle, and fibroblasts, as well as by inflam-
matory cells. Chemokines are a family of more than 40 small (8-11 kDa)
cytokines that have been defined primarily by their ability to mediate leuko-
cyte chemotaxis. Chemokines have been divided into four major families on
the basis of the spacing of the most amino-terminal of four conserved
cysteine residues, including the C, CC, CXC, and CX3C families, where X
represents any amino acid (48).
Bronchopulmonary inflammation of COPD is characterized by CD8,
Tc1 cells, and neutrophils. Recent reports demonstrate that T cells from
the bronchial mucosa of patients with COPD predominantly express the
chemokine receptor CXCR3 (49,50) and produce interferon-
g
(IFN-
g
),
suggesting that these cells elaborate type I cytokines (Fig. 2).
The CXCR3 chemokine receptor binds three highly potent, inflamma-
tory-inducible CXC chemokine agonists, e.g. interferon (IFN) -
g
-inducible
protein 10 (CXCLl0
=
IP-10), monokine induced by IFN-
g
, and interferon-
inducible T-cell
a
-chemoattratant (CXCL11
=
I-TAC) (52). CXCR3 is selec-
tively expressed by activated T cells, B cells, natural killer cells (NK) and a
subset of circulating blood T cells consisting mainly of CD45RO
รพ
memory
cells; a subset of dendritic cells as well as intraepithelial lymphocytes in nor-
mal and inflamed tissues. In addition, CXCR3 is constitutively expressed by
endothelial vessels of medium and large caliber but not in small vessels.
Figure 2
The potential role of cytokine to chemokine regulatory networks in the
development of inflammation in asthma and COPD. (From Ref. 51.)
