Download Cytokines

Cytokines
Linrong Lu
ZJU Instiitute of Immunology
[email protected]
l
http://mypage.zju.edu.cn/personnelCard/llr
Definition
Cytokines
C
t ki
are low-molecular
l
l
l
weight
i ht
regulatory proteins （ glycoproteins)
secreted by white blood cells and
various other cells in the body in
response
p
to a number of stimuli.
These proteins mediate and regulate
immune and inflammatory reactions.
Cytokines
1. General Properties of Cytokines
2. Functional Categories of cytokines
3. Cytokine receptors and signal transduction
4. Cytokines
y
that mediate and regulate
g
innate
immunity
5. Cytokines that regulate Adaptive Immunity
6. Cytokines
y
that stimulate Hematopoiesis
p
7. Cytokine related diseases
8. Therapeutic Use of cytokines
1 General Properties
1.
1.1 Cytokine secretion is a brief, self-limited event;
1.2 The actions of cytokines are often pleiotropic and
r un ant;
redundant;
1.3 Cytokines often influence the synthesis and actions
of
f other
h cytokines
k
;
1 General Properties
1.
1.4. Cytokine actions may be local and systemic ;
1.5. Cytokines initiate their actions by binding to
specific membrane receptors on target cells;
1.6. The cellular responses
p
to most cytokines
y
consist of
changes in gene expression in target cells, resulting
in the expression of new functions in the target
cells
ll
1.1 Cytokine secretion is a brief, self-limited
event;
Cytokine secretion upon CpG treatment
IL2 secretion by CD4 T cells
upon TCR engagement
1.
1
2.
3.
4.
5.
6.
Ab
Absent
nt from
f m unstimulated
n tim l t d cells.
ll
Rapid transcriptional activation with stimulation.
Can have post-translational control;
Rapid
p secretion.
Short-lived transcripts and proteins.
Transcription ceases when stimulus abates.
1.2 The actions of cytokines are often
pleiotropic and redundant
One cytokine can target different target cells
1.2 The actions of cytokines are often
pleiotropic and redundant
Different cytokines can exert similar effect
1.3
Cytokines often influence the
synthesis
th i and
d actions
ti
of
f other
th
cytokines ;
Cytokines can work together or against each other
1.3 Cytokines
often influence
the synthesis and
actions of other
cytokines
(Cascade effect)
One cytokine can
induce another
cytokine
cytok
ne and so
on…….
Cytokine
C
t kin
Network
1.4 Cytokine actions may be local
and/or systemic
1.5
Cytokines initiate their
actions by
y binding
g to
specific
membrane
receptors on target cells.
1.6 The cellular responses to
most cytokines consist of
changes in gene expression
in target
g
cells,, resulting
g in
the expression of new
functions in the target cells
2. Functional Categories of cytokines
Cytokine families based on their biological function
similarity：
2.1 Interleukines
2.2 Interferons
23 C
2.3
Colony
l
S i l i F
Stimulating
Factors
2.4 TNF family
2 5 Chemokines
2.5
2.6 Transforming Growth Factors
2.7 Other cytokines
y
(MIF,
(
, c-kit ligand,
g
, LIF , OsM
CNTF etc.
2.1 Interleukins (IL)
1 First seen to be expressed by white blood cells (leukocytes),
1.
(leukocytes)
The term interleukine, (inter-) as a means of communication,
(-leukin) deriving from the fact that many of these proteins
are produced by leukocytes and act on leukocytes.
2. It has since been found that interleukins are produced by a
wide variety
y of body
y cells. The function of the immune
system depends in a large part on interleukins,
And rare deficiencies of a number of them have been described, all
featuring autoimmune diseases or immune deficiency. The majority of
interleukins are synthesized by helper CD4+ T lymphocytes, as well as
through monocytes, macrophages, and endothelial cells. They promote
the development and differentiation of T, B, and hematopoietic cells.
2.2 Interferons (IFNs)
Interferons (IFNs) are natural cell-signaling proteins produced by the
cells of the immune system in response to challenges such as viruses,
parasites
i
and
d tumor cells.
ll
Interferons assist the immune response
p
by
y inhibiting
g viral replication
p
within host cells, activating immune cells (natural killer cell and
macrophages), increasing antigen presentation to T Lymphocytes, and
increasing
n
ng the resistance
n of
f host cells to viral infection.
nf
n.
There are 3 known classes of interferons; type I, type II and type III.
All classes are very important in fighting viral infections.
infections Their
presence also accounts for some of the host symptoms to infections,
such as sore muscles and fever.
2.3 Colony-stimulating factor
Colony-stimulating factors (CSFs) are secreted glycoproteins which
bind to receptor proteins on the surfaces of hemopoietic stem cells
and
d thereby
th
b activate
ti t intracellular
i t
ll l signaling
i
li pathways
th
which
hi h can cause
the cells to Proliferate and differentiate into a specific kind of blood
cell (usually white blood cells）。
2.3 Colony-stimulating factor
The name “colony-stimulating factors” comes from the method by which
they were discovered. Hemopoietic stem cells were cultured in semi solid
matrix which prevents cells from moving around,
around so that if a single cell starts
proliferating, all of the cells derived from it will remain clustered around the
spot in the matrix where the first cell was originally located, and these are
referred
f
to as "colonies."
. It w
was therefore
f
possible to add various
p
u substances
u
to cultures of hemopoietic stem cells and then examine which kinds of colonies
(if any) were "stimulated" by them.
The substance which was found to stimulate formation of colonies of
macrophages, for instance, was called macrophage colony-stimulating factor,
for granulocytes, granulocyte colony-stimulating factor, and so on.
2.4 Tumor necrosis factors
Tumor necrosis factors (or the TNF-family) refers to a group of
cytokines family that can cause cell death.
TNF acts via the TNF Receptor (TNF-R) and is part of the
extrinsic p
pathway
y for triggering
gg
g apoptosis.
p p
Tumor
um necrosis
n
f
factor-alpha
p ((TNF-α)
NF ) is the m
most w
well-known
n wn
member of this class, and sometimes referred to when the term
"tumor necrosis factor" is used.
Tumor necrosis factor-beta (TNF-β), also known as lymphotoxin is
a cytokine that is induced by interleukin 10 [3]
2.5 Chemokines
Chemokines (Greek -kinos, movement) are a
family of small cytokines, or proteins
secreted by cells. Their name is derived
fr m th
from
their
ir ability
bilit tto induc
induce dir
directed
ct d
chemotaxis in nearby responsive cells; they
are chemotactic cytokines.
Proteins are classified as chemokines
according
g to shared structural
characteristics such as small size (they are
all approximately 8-10 kilodaltons in size),
and the presence of four cyste
cysteine
ne res
residues
dues
in conserved locations that are key to
forming their 3-dimensional shape.
2.5 Chemokines
R
Receptors:
t
2
28
1
17
2.6 Transforming growth factor
(TGF)
Transforming
T
f
i growth
th factor
f t (sometimes
(
ti
referred
f
d tto as Tumor
T
growth factor, or TGF) is used to describe two classes of
polypeptide growth factors, TGFα and TGFβ.
TGFα is upregulated in some human cancers. It is produced in
macrophages,
p g
brain cells, and keratinocytes,
y
and induces
epithelial development.
TGFβ exists in three known subtypes in humans, TGFβ1, TGFβ2,
and TGFβ3. These are upregulated in Marfan's syndrome and
some human cancers, and play crucial roles in tissue
regeneration cell differentiation,
regeneration,
differentiation embryonic development,
development and
regulation of the immune system.
Pleiotropic effects of TGF-β on leukocytes. All leukocytes produce and
respond to TGF-β. The yin-yang symbol illustrates the fact that TGF-β
exerts both stimulatory and inhibitory effects on immune cells
cells. Selected
immunological processes regulated by TGF-β are depicted (MC, mast cell;
EO, eosinophil; MO/MΦ, monocyte/macrophage).
TGF-β
β regulation
g
of T cell
responses
TGF-β blocks T cell proliferation by inhibiting IL-2 production via Smad3 and by
downregulating the expression of cyclinD2 and E
E, CDK4,
CDK4 and c-myc.
c myc TGF
TGF-β
β inhibits
differentiation of Th1 and Th2 cells through suppressing the expression or function of Tbet/Stat4 and GATA-3/NFAT. Mechanisms involved in TGF-β inhibition of CTL
differentiation are not well understood, although inhibition of c-myc and T-bet expression is
suggested TGF
suggested.
TGF-β
β induces FoxP3 expression and the generation of Tregs.
Tregs TGF-β
TGF β also prevents
T cell activation-induced cell death (AICD) through inhibiting c-myc-mediated FasL
expression and other unknown mechanisms
Ming
g Li’s work
To study the precise function
and mechanism of TGF-beta
control of immune responses,
responses
we used a tissue-specific genetargeting
technique
to
i
inactivate
ti t TGF-beta
TGF b t and
d TGFTGF
beta receptor in various cell
types in mice. These studies
revealed TGF-beta as a critical
regulator of T lymphocyte
development,
p
,
homeostasis,,
tolerance to self-antigens, and
differentiation
during
the
immune responses.
responses
Ming Li,
Sloan Kettering
Richard Flavell ，
Yale
3. Cytokine
y
Receptors
p
Immunoglobin domain Receptors in this family has the
mm
g
domain
m
named
m after
f
the immunoglobulin
mm
g
immunoglobin
molecules
This receptor family have conserved amino acid sequence motifs in the
extracellular domain consisting of four positionally conserved cysteine
residues (CCCC) and a conserved sequence of tryptophanserine
tryptophanserine-(( any
amino acid)- tryptophan-serine (WSXWS,where X is the nonconserved
amino acid). The receptors for all the cytokines classified as
hematopoietins belong to the class I cytokine receptor family,
family which
also is called the hematopoietin receptor family.
The class II cytokine receptors possess the conserved CCCC motifs,
motifs but lack
the WSXWS motif present in class I cytokine receptors. Initially only the
three interferons, , , and , were thought to be ligands for these receptors.
However, recent work has shown that the IL
IL-10
10 receptor is also a member of
this group.
Tumor necrosis factor receptors
p
((TNFRs)) are cytokine
y
receptors
p
that
binds TNFs (TNF).
They were also called death receptors since they can transduce signals
lead to cell death,
Chemokine receptors are receptors of chemokines. There have been 19 distinct
chemokine receptors described in mammals.
mammals They each have a 7 transmembrane
(7TM) structure and couple to G-Protein for signal transduction within a cell,
making them members of a large protein family of G protein-coupled receptors.
Following interaction with their specific chemokine ligands, chemokine receptors
trigger a flux in intracellular calcium (Ca2+) ions (calcium signaling). This causes cell
responses, including the onset of a process known as chemotaxis that traffics the
cell to a desired location within the organism.
Another feature common to most of the hematopoietin (class I cytokine)
y
receptor
p
families is multiple
p subunits,, often
and the class II cytokine
including one subunit that binds specific cytokine molecules and another
that mediates signal transduction.
Cytokines have numerous functions.
functions
Mediators and regulators of Innate Immunity
Mediators and regulators of adaptive immunity
Stimulators of hematopoiesis
The innate immunity comprises the cells and mechanisms that defend the
host from infection,, in a non-specific
p
manner. Innate immune systems
y
provide immediate defense against infection, but does not confer longlasting or protective immunity to the host.
The adaptive immune system is composed of highly specialized, systemic
cells and processes that eliminate or prevent pathogenic challenges. It can
recognize and remember specific pathogens (to generate immunity), and
to mount stronger attacks
k each
h time the
h pathogen
h
is encountered.
d It is
adaptive immunity because the body's immune system prepares itself for
future challenges.
Main Cytokines in innate immunity
TNF
I
Interleukin-1
l ki 1
Interleukin-12
Type I interferons
Interleukin-10
Interferon-γ (IFN-γ):
TNF
Mediator of acute inflammatory
y response
p
to
gram-negative bacteria and other infectious
microbes.
Major cellular source is activated mononuclear
phagocytes (Macrophage stimulated with LPS);
Can be membrane protein or
released (trimer)
Signaling
g
g by
y TNF receptors:
p
Biological Actions of TNF
R
Recruitment
of
f neutrophils
h l and
d
monocytes
to
sites
of
infection and activate these
cells to eradicate microbes;
Large
amount
cause
systemic
of
TNF
can
clinical
and
pathological abonomalities
Septic shock (endotoxin shock):
vascular collapse.
Int l kin 1 (IL-1):
Interleukin-1
(IL 1):
Mediator
M
di
of
f inflammatory
i fl
response to infectious
i f
i
microbes.
M j
Major
cellular
ll l
source is
i activated
ti t d mononuclear
l
phagocytes;
T
Two
f
forms
IL 1 and
IL-1α
d IL-1β
IL 1β
(30% homologous), IL-1 β
need to be cleaved
l
to be
active (ICE：IL-1βconvertingenzyme)
Similar effect as TNF
Interleukin-12
Produced by activated
mononuclear phagocytes and
dedritic cells
Stimulate IFN production by NK
and T lymphoctyes.
Enhance
E
h
cytolytic
t l ti functions
f
ti
of
f
activated NK and CTL cells.
Is a link between innate and
adaptive immunity.
Type I interferons:
T
i t f
IFN
IFN-α
( 20) and
(∼20)
d
IFN-β
Sti l t d by
Stimulated
b viral
i l infection,
i f ti
mediate
di t early
l
innate immune response to viral infectionsestablishment of “antiviral
antiviral state
state”
Bi l i l Actions:
Biological
A ti ns:
Inhibits viral replication
Increase expression of
f MHC
MH I
Stimulate the development of Th1 cells
Inhibits the proliferation of many cell time.
Interleukin-10:
IL10 is an inhibitor of activated
macrophages and dedritic cells and
is thus involved in the control of
innate immune reactions and cellmediated immunity.
Produced by activated macrophages.
Inhibits the production of IL12;
Inhibits
the
expression
of
costimulators and MHC II.
IL10-/- develop inflammatory bowel
disease.
Interferon-γ (IFN-γ):
IFN-γ is the principal macrophage-activating cytokine
that provide the means by which T lymphocytes and NK
cells activated macrophages to kill phagocytosed
microbes.
IFN-γ stimlates expression of MHC I and MHC II
molecules
l
l and
d costimulators
ti l t
on APCs.
APC
Cytokines mediate and regulate adaptive immunity
Interleukin-2
Interleukin-4
Interferon-γ
Transforming Growth Factor-β
Interleukin-2:
IL2 is a growth factor for antigen
antigen-stimulated
stimulated T
T-lymphocytes
lymphocytes and is
responsible for T cell clonal expansion after antigen recognition.
Promote proliferation of antigen-specific
antigen specific T cells;
Promote the proliferation and differentiation of other immune
cells;
Essential for the development and proliferation of CD4+FoxP3+
Tregs (a subfamily of T helper cells exert regulatory function).
Interleukin-4 (IL4):
IL4 is the major
j stimulus for the p
production of IgE
g antibodies and
for the development of Th2 cells from naïve CD4+ helper T cells.
Biological Actions:
Stimulate B cell Ig heavy chain class switching to IgE isotype
Stimulate Th2 cells
Inhibit Th1 differentiation and cell-mediate immune response
Interferon-γ (IFN-γ):
The role of IFN-γ in adaptive immunity is to promote the
differentiation of Th1 helper cell and cell-mediated immune reaction.
IFN- γ can also inhibite the development of Th2 helper cells
Transforming Growth Factor-β (TGF-β):
Inhibit the proliferation and action of lymphocytes and other
leukocytes
Stimulate the differentiation of Tregs and Th17 cells (with IL6).
IL6)
Signal II
Signal I
Si
Signal
l III
Th differentiation governed
by signal III (cytokines)
Revised Th Differentiation
Th17 and Treg Cells
•
Th17 (CD4+, FoxP3-))
– IL-17 is a proinflammatory cytokine
– Promotes secretion of
pro-inflammatory
y
(IL-6)
(
) from
cytokines
fibroblasts, epithelial and
endothelial cells.
– Th17 cells are critical to
anti-bacterial immunity.
– Overexpression of IL-17
is associated
ass ciated with
rheumatoid arthritis, SLE,
MS and asthma
•
T
Treg
(CD4+, Foxp3
F
3+)
– Natural (develop in the
thymus)
• Prevent effector T
cell development in LN
– Induced (develop in the
periphery)
• Develop under the
influence of TGF-ß
• Inhibit effector T cell
function in periphery.
Th9 cells
ll , Is
I it Real?
R l?
REFERENCES: Veldhoen M et al Transforming growth factor-beta
'reprograms'
p g
the differentiation of T helper
p 2 cells and promotes
p
an
interleukin 9-producing subset. Nature Immunology 9(12): 1341-1346
(2008)
Cytokines in
hematopoiesis
C t ki and
Cytokine
d disease
dis s
Cytokine-related
Cytokine
related diseases
Bacterial septic shock
endotoxins (cell walls) stimulate production
of IL
IL-11 and TNF
TNF-α
α
Cancers of lymphoid system
system- overproduction
of cytokines such as IL-6 (B-cell) or IL-5
(Hodgkin’ss disease) or IL
(Hodgkin
IL-2
2 (adult T
T-cell
cell
leukemia)
Chagas’ disease (parasitic)- suppression of
α-subunit
α
subunit of IL
IL-2
2 receptor
Cytokine
y
therapies
p
Interferons
IFN-α- certain types of tumors
IFN-β- multiple sclerosis
th s are antiviral
these
ntivi l
IFN-γ- chronic granulomatous disease
IL-2- certain types of cancer
infusion
LAK (lymphokine-activated killer) cells
TILs (tumor-infiltrating lymphocytes)
GM-CSF- immune deficiencies
TNF (tumor
(t
necrosis
i factors)
f t )
TNF-α and β
In some cases inhibit proliferation of tumor
cells
ll but
b t nott normall cells
ll
M d
May
damage vascular
l endothelial
d th li l cells
ll in
i
tumors, thus inhibiting blood supply
t the
to
th tumor
t
Cytokine related technology
ELISA and FACS ((Cytokine
y
detection))
Recombinant protein (gene engineering，
P d
Production
i of
f large
l
amount of
f cytokines)
ki
)