136
Cytokines: Interleukins
Tab. 5
The biological activities of interleukins.
Interleukin
Principal activities
IL-1
α
– Activates mature T cells to produce IL-2 and express IL-2R.
– Costimulant of proliferation and activation of B cells and hematopoietic progenitor
cells.
– Induces proinflammatory cytokines, e.g. TNF
α
, IL-6, and other mediators
depending upon cell type.
– Increases expression of endothelial cell adhesion molecules.
– Induces neutrophil accumulation
in vivo
.
– Induces fever and hypotension.
IL-1ra
– Inhibits the activities of IL-1
α
/ß by competing for IL-1R.
IL-2
– Stimulates T-cell proliferation and differentiation.
– Activates NK and LAK cells.
– Promotes proliferation of and Ig secretion in activated B cells.
– Causes vascular leak syndrome
in vivo
at high doses.
IL-3
– Acts in combination with lineage-restricted cytokines to stimulate proliferation and
differentiation of hematopoietic progenitors of macrophages, neutrophils,
basophils, eosinophils, mast cells, megakaryocytes, and erythrocytes.
– Supports the proliferation of early multipotential bone marrow stem cells.
IL-4
– B-cell growth and differentiating factor, induces IgE synthesis.
– Generates Th2 cell subset from naive Th0 cell population.
–A
n
t
a
g
o
n
i
s
to
f
I
FN
γ
.
IL-5
– Stimulates generation of eosinophils from hematopoietic precursors.
– Possible involvement in B-cell differentiation and Ig class switching.
IL-6
– Growth factor for many transformed and tumor cells.
– Costimulant of proliferation in thymocytes and IL-3-dependent hematopoietic
progenitors, and of IL-2 production in mature T cells.
– Terminal B-cell differentiation factor.
– Hepatocyte stimulating factor; inducer of acute-phase protein synthesis.
IL-7
– Supports the proliferation of immature B- and T cells.
– Possible involvement in proliferation and activation of mature T cells.
IL-8
– Chemoattractant for neutrophils and T cells.
– Stimulates neutrophil activation and degranulation.
IL-9
– Augments mast-cell proliferation response to IL-2.
– Sustains antigen-independent growth of certain Th cells.
IL-10
– Inhibitor of cytokine/interleukin synthesis by Th1 cells.
– Suppressant of macrophage functions, including down regulation of inflammatory
cytokine production.
– Enhances B-cell proliferation and Ig synthesis.
– Growth factor for B-cell tumors.
IL-11
– Synergistic factor for IL-3-dependent proliferation of bone marrow progenitors
(similar to IL-6 in this respect), particularly megakaryocyte colonies.
– Can act on hepatocytes to induce acute-phase protein synthesis.
IL-12
– Stimulates the differentiation of naive Th0 cells into the Th1 cell subset and
thereby is an initiator of cell-mediated immunity.
–I
n
d
u
c
e
s
I
FN
γ
production with IL-18 as costimulant.
– Stimulates the proliferation and activity of NK cells and mature T cells.
IL-13
– Induces B-cell proliferation and differentiation (similar to IL-4).
– Inhibits inflammatory cytokine synthesis by monocytes/macrophages.
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