Wondershare EdrawMind
MindMap Gallery Medical Immunology-Ninth Edition Human Health Blue Life and Death Love
- 32
Medical Immunology-Ninth Edition Human Health Blue Life and Death Love
Used for review and preview by medical students who use medical exemption
Edited at 2023-11-15 16:34:46
- bacteria
This is a mind map about bacteria, and its main contents include: overview, morphology, types, structure, reproduction, distribution, application, and expansion. The summary is comprehensive and meticulous, suitable as review materials.
- Plant asexual reproduction
This is a mind map about plant asexual reproduction, and its main contents include: concept, spore reproduction, vegetative reproduction, tissue culture, and buds. The summary is comprehensive and meticulous, suitable as review materials.
- Reproductive development of animals
This is a mind map about the reproductive development of animals, and its main contents include: insects, frogs, birds, sexual reproduction, and asexual reproduction. The summary is comprehensive and meticulous, suitable as review materials.
Medical Immunology-Ninth Edition Human Health Blue Life and Death Love
- bacteria
This is a mind map about bacteria, and its main contents include: overview, morphology, types, structure, reproduction, distribution, application, and expansion. The summary is comprehensive and meticulous, suitable as review materials.
- Plant asexual reproduction
This is a mind map about plant asexual reproduction, and its main contents include: concept, spore reproduction, vegetative reproduction, tissue culture, and buds. The summary is comprehensive and meticulous, suitable as review materials.
- Reproductive development of animals
This is a mind map about the reproductive development of animals, and its main contents include: insects, frogs, birds, sexual reproduction, and asexual reproduction. The summary is comprehensive and meticulous, suitable as review materials.
- Recommended to you
- Outline
medical exemption
Introduction
Immune Function
immune defense
immune surveillance
immune homeostasis
immune type
innate immunity
innate immunity
non-specific immunity
Immune Cells
Granulocytes
Mononuclear/macrophages
NK cells
DC cells
adaptive immunity
acquired immunity
specific immunity
immune organs and tissues
antigen
Antibody
complement system
Cytokines
leukocyte differentiation antigens and adhesion molecules
leukocyte differentiation antigen HLDA
Marker molecules on the cell surface during the differentiation of hematopoietic stem cells into different lineages, differentiation stages of each lineage, and activation of mature cells
Different surface marker proteins are present at different stages
The direction of differentiation can be identified by observing HLDA
transmembrane glycoprotein
Extracellular domain
transmembrane region
cytoplasmic region
Homogeneous differentiation antigens are grouped into the same differentiation group CD
Classification
receptor
antigen recognition receptor
adhesion molecules
Molecules that mediate binding between cells or between cells and the extracellular matrix
major histocompatibility complex MHC
B cells
T cells
Antigen presenting cells APC
comprehensive
T cell-mediated adaptive immune response
B cell-mediated specific immune response
immune organs and tissues
immunity
The body's ability to recognize and eliminate antigenic substances
Immune system classification
Immune Cells
immune molecules
Immunoglobulin
complement
Biomolecules that are lysable in the presence of antibodies
Cytokines
immune organ
center
marrow
Contains hematopoietic stem cells
differentiation
immune cells in blood
monocytes
Granulocytes
progenitor-B cells
Move to bone marrow maturation
progenitor-T cells
Move to thymic maturation
Finally settled in lymph nodes
When dysfunction occurs
hematopoietic dysfunction
Both humoral and cellular immunity disorders
Where blood cells and immune cells develop
Thymus
Function
Promote T cell development and maturation
Immunomodulatory effect
Establish and maintain immune tolerance
obstacles
Cellular immune disorders
Regulatory imbalance
The body is prone to allergies and rejection reactions
Periphery
Lymph nodes
structure
cortical area
Superficial cortical area
The place where B cells settle and take effect
naïve B cells
B lymphoblasts
plasma cells
primary lymphoid follicle
secondary lymphoid follicles
Move cells within the follicle to the medullary cord
germinal centers produced during immune response
deep cortical area
T cell colonization
also called paracortical area
medullary region
number of cells
75%T cells
25%B cells
Function
BT cell settlement site
site of adaptive immune response
filter lymph fluid
lymphocyte recirculation
Inject into the veins on both sides under the clavicle
Injected into various lymphoid organs through high endothelial venules
spleen
Function
site of immune response to blood-borne antigens
Synthetic active substances
Complement and Cytokines
filter blood
store blood
Hematopoietic function
early hematopoietic organs
mucosa-associated lymphoid tissue MALT
Intestine
nose
bronchus
The body’s important defense barrier
Generate mucosal local immune response
secretory lgA
Function
The place where the body produces an immune response
Place where TB cells settle after maturation
antigen
definition
Substances that cause the body to produce an immune response
immune characteristics
Immunogenicity
The ability of TB cells to respond to antigens
immunoreactivity
also called antigenicity
The ability of response substances produced by TB cells to specifically bind to antigens
Substances that have both are called complete antigens
immune specificity
An antibody can only bind to the corresponding antigen
Decisive factors in inducing antibody production
response mechanism
gauge
The smallest unit of recognition of immune response
epitope
Essentially a chemical group
Binding site of TB cell-specific antigen receptor (TBCR)
category
sequential epitope
Also called linear epitope
spatial epitope
T epitope
Presented by APC cells
MHC restrictive
Requires matching MHC molecules produced by the T cell itself
Carrier determinants, sequential epitopes, cryptic epitopes
B epitope
Unlimited
functional epitope
half-epitope-carrier reaction
B cells recognize hapten
T cell recognition vector
What can be directly recognized by TCR is the T epitope
Certain small drug molecules can be considered haptens
Haptens are not immunogenic
Inability to produce an immune response in the body
Requires Th cells to help form
TD-Ag (T cell dependent antigen) is produced from this
cross-reactivity
Some antigens have the same epitope
Case
Cowpox used to prevent smallpox
Rheumatoid arthritis drugs attack heart muscle
Factors affecting immunogenicity
antigen itself
Foreign body property
The more distant the genetic relationship, the greater the originality.
Not a decisive factor in antibody production
chemical properties
High molecular weight substances and proteins
molecular weight
Large quantity and high potency
Molecular Structure
Structural complexity is positively related to originality
molecular conformation
Chemical group position and type
accessibility
Physical properties
Polymerized substances are more original
Host characteristics
How antigens enter the body
subcutaneous/intradermal injection
intramuscular injection
intravenous injection
Oral immunization can easily produce immune tolerance
Longer cycle injections are more effective
Adding adjuvants during injection can change the degree and type of immunity
Antigen type
Activation method
T cell dependent antigen TD-Ag
Antigen-presenting cell processing is required to activate B cells
TI-Ag
Only repeated B epitope
The antibodies produced are mainly IgM
Cannot induce the production of multiple antibodies
Kinship
heterophile antigen
Common antigens between different species
leading to cross immunity
xenoantigen
Different types of antigenic substances
Macromolecules such as proteins
Microorganisms and their products
alloantigen
Different antigens among different individuals of the same species
Blood Group and Histocompatibility Antigens HLA
autoantigen
When the chemical properties of the own substance change, the immune sequestered substance is released and is regarded as an antigen.
idiotype antigen
Present intracellular antigen
endogenous antigen
Viral substances and tumor cell substances synthesized inside APC cells
Recognized by TCR of CD8⁺T cells
Combines with MHC I molecules to form a complex
exogenous antigen
External proteins or polysaccharides
Recognized by TCR of CD4⁺T cells
Combines with MHC II molecules to form a complex
Used for differences in MHC gene polymorphisms and other immune regulatory genes, which genetically determine whether or not the immune response of different individuals to the same antigen is different and the degree of response is different.
non-specific immune stimulants
superantigen
Essentially cloned cells
No MHC restriction
There are far more T lymphocytes activated at one time than ordinary antigens
application
Staphylococcus aureus enterotoxin
Adjuvant
Injecting the body with antigen before or at the same time can change the degree and type of immune response
effect
Change the physical properties of the antigen
Enhance immunogenicity
Speed up antigen presentation
Stimulate lymphocytes to strengthen immune response
type
BCG vaccine
Cytokines
Liposomes
Freund's complete adjuvant
Freund's incomplete adjuvant
AntibodyAb
chemical nature
Immunoglobulins that specifically bind antigens
Immunoglobulins are contained in antibodies
structure
2 identical heavy chain H
2 identical light chains L
The two light chains of natural antibodies are always the same
Covalently connected by disulfide bonds, in a Y shape
Each peptide chain has 2-5 domains
Partition
The amino acid sequence at the head end near the N terminus changes greatly.
variable region V
High Variability Region HVR
Also called complementarity determining region CDR
Key parts of antibody specificity
Binds to epitope
The degree of change is greater
H and L each have three areas
skeleton area FR
Used to maintain the spatial configuration of the antibody
Conducive to refined and specific binding to antigens
1/4 of the heavy chain
Light chain 1/2
Divided into κ and λ chains
There are two types of Ab
Antibody L chains with the same function can be kappa or lambda
There are two types of 5 Abs
Immunoglobulin κ in human serum: λ=2:1
Subtypes
Individual amino acid differences in Cλ region
There is not much change near the C end.
constant region C
The Cʰ region determines the globulin class
Classification based on differences in antigenicity (immunoreactivity) of the H chain constant region (CH region)
Number and position of disulfide bonds within the chain
Number of domains
γαμεδ 5 heavy H chains
Compatible with IgGAMED type 5 antibodies
Subcategories can also be divided based on differences in the hinge area.
The C region Aa sequences of different antigens in the same individual are basically the same
Immunogenicity is the same
The length of the Cᴸ region of different Ab types is the same
Area Cʰ is different
IgM and IgE have four domains
IgAED only three
hinge area
Located between CH1 and CH2
Rich in proline
Zipper structure
Good elasticity
Make both chains bind epitopes simultaneously
However, it is unstable and easily digested by enzymes.
IgM and IgE do not have hinge regions
Auxiliary ingredients
J chain
Convert antibody monomers into multimers
IgA dimer
IgM pentamer
IgEDG without J chain
synthesized by plasma cells
Secretory tablet
Participates in the formation of secretory IgA
Mediates its transport from the mucosa to the mucosal surface
Anti-infection locally on mucous membranes
Protect hinge area
Secreted by mucosal epithelial cells
Hydrolysis of Ab
hydrolase
papain
2 Fab and a Fc
Pepsin
Divided into 1 F(ab')₂ and some pFc'
F(ab')₂=2 Fab hinge areas
Ab immunoreactivity and immunogenicity
definition
anti-antibodies – secondary antibodies
three serotypes
Isotype
allotype
The determinant is in area C
unique type
Antibodies from the same individual have different immunogenicity
Corresponding secondary antibodies can be produced in the body
Determinants are in VL and VH regions
Ab function
Zone V
Neutralization
Binds to antigen to remove its toxicity
Area C
activate complement
C1q binding site of Cᴴ2 3 exposed
activate complement system
Mainly activated by IgM G
Binds to Fc receptor (FcR)
conditioning effect
Fab segment binds to antigenic epitope
Fc segment connects to macrophage FcR
Promote MΦ cells to phagocytose foreign bodies
Antibody-Mediated Cytotoxicity (ADCC)
mediated by IgG A
non-specific immunity
Fab segment binds to antigenic epitope
Fc segment connects to macrophage FcR
Prompt NK cells to kill antigens
Antibodies bind white blood cells specifically
Killing of target cells by cells expressing FcR is non-specific
Mediates type I hypersensitivity reactions
The Fc segment of IgE binds to mast cells
play a role in the immune response again
Crosses the placenta and mucous membranes
IgG crosses the placenta and enters the fetus
SIgA secreted to mucosal surfaces
Modulate immune response
Characteristics and functions of each Ig
IgG
The highest content in serum
75%-80%
There are four subcategories
Longest half-life
Crosses the placenta
Placental trophoblast cells have corresponding FcR
The main force of fetal resistance to infection
appear earlier
three months old
Has conditioning effect
Promote phagocytes to engulf antigens
CH3 has FCγRI
Grab the antigen with your hands and step on the phagocytes
CH2 of lgG1 and 3 can bind complement
Hanging supplements from the waist, activating complements
Antibody-Mediated Cytotoxicity (ADCC)
Fab segment binds to antigenic epitope
Fc segment connects to macrophage FcR
Prompt NK cells to kill antigens
Reimmune primary antibodies
IgA
divided into
serotype
secretory type
Babies receive SIgA through colostrum for natural passive immunity
After polymerization, it can be used to activate the alternative complement pathway.
IgM
The largest molecular weight
Only exists in serum
pentavalent antibody
Monomers constitute BCR
Primary humoral immunity is the earliest
IgM appears first after immunization
The earliest antibodies produced during ontogeny
Early diagnostic indicators of body infection
Antibodies with the strongest ability to activate complement
IgE
Serum content is the lowest
Cytotropic antibodies
Cᴴ2 3 (Fc segment) binds to FcεR I of mast cells and basophils causing type I hypersensitivity reactions
antiparasitic immunity
IgD
Membrane-bound IgD (mIgD) is a marker of B cell maturation
Only mIgM is expressed when immature
B cells express both mIgM and D after maturation
mIgD disappears after activation
complement systemcomplement
Nature
Precisely regulated protein response system
Components
intrinsic components
Proteins involved in complement activation in plasma body fluids
C1-9
Cq1
Has lipase activity
C1r can be activated
C3
is a common component of the three pathways
The main factor that amplifies the activation effect
Slowly hydrolyzed in serum to produce C3b
A very small part binds to the activator and binds to factors B and P
Formation of C3 convertase cleaves more C3
C3a
free in serum
inflammatory mediators
C3b
Binds to B cell CR1 to promote B cell proliferation and differentiation
C4
Product of C1
Very unstable
be lysed immediately
C5a
Chemotactic
important inflammatory mediator
complement regulatory protein
Proteins that control the properties of complement by activating key enzymes in the pathway
B, D, H, I factors
complement receptor CR
A receptor that binds to activated complement active fragments and mediates biological effects
Features
unstable
Decomposes rapidly in hot environment
Stable content
Does not increase with antigen stimulation
Three complement activation pathways
Classical approach
stage
identification stage
Mainly activated by antigen complexes of IgG1~3 and IgM
Binds to C1q
Complement binding site on the Fc region of the antibody
IgM has the strongest activation ability, followed by IgG1 and 3
IgG2 is the weakest
activation stage
C3 convertase C4b2a
C4b combined with C2a
Mg²⁺Participate
C5 convertase C4b2a3b
Effect stage
Formation of MAC attack complex
C5b6789n complex
Lots of C9 synthesis
activation sequence
C1q－C1r－C1s-4-2356789
Features
Requires antibodies to start
Participate in secondary immunization
Immunity plays a role in the late stages of infection and recovery
C2 is the least in serum
rate limiting component
C3 is the most abundant in serum
Ca²⁺Participate
specific humoral immunity
MBL pathway
Activated by N-galactosamine and mannose on the surface of bacteria or viruses (mannose lectin) MBL
MBL→Related serine protease MASP→C423456789
MASP1 generates C3 convertase as a bypass
MASP2 generates C3 convertase for classical
Features
No antibodies required
Acts during the early stages of infection and during first infection
Produce cross-promotional effects on the other two pathways
When MBL is normal, there is very little in the serum, and it increases when inflammation occurs.
MASP is a C1 analog
bypass pathway
Direct activation of C3 by bacterial, fungal or viral infection of cells (bacterial lipopolysaccharide, peptidoglycan, zymosan) or agglutinated IgG4 IgA
356789
So invertase enzymes all start with C3
There are low levels of C3b in the serum under physiological conditions
The activator protects C3b from inactivation and binds to factor B large fragment (Bb) and forms C3 convertase
Features
There is positive feedback regulation
C3 convertase C3bBb (P)
Factor B is cleaved by factor D
P factor binds to invertase
C5 convertase C3bnBb (P)
The earliest complement activation pathway
Non-specific line of defense against microbial infections
IgA, E and IgG4 are difficult to activate complement by themselves, but they can activate complement through this pathway after agglutination to form polymers.
No antibodies required
Acts during the early stages of infection and during first infection
Able to identify oneself and others
non-specific immunity
Regulation of complement
MAC
Homology restriction molecule HRF
Also called C8 binding protein
S protein
Membrane reactive lysis inhibitor MIRL
Also known as CD59
Clusterin
invertase
C1 inhibitor C1NH
CR1
C4 binding protein
Decay acceleration factor DAF
The defect causes nocturnal paroxysmal hemoglobinuria (PNH).
H factor
I factor
Membrane accessory protein MCP
Factors H and I inhibit C3b
Classification
membrane protein
soluble protein
effect
Prevent complement self-activation
Change the mode of action of complement on substrates
Protect the body from complement destruction
significance
body's innate immune defense components
Maintain internal environment stability
The mechanism by which antibodies exert immunity
amplify the reaction
immune memory
Classical approach
The bridge between innate immunity and adaptive immunity
biological functions
role of inflammatory mediators
Mediates inflammatory response
C3-5a
Anaphylatoxin effects
C5a has the strongest chemotactic activity
conditioning effect
Complement binding to complement receptors on phagocytes
Promote macrophage phagocytosis
C3b, C4b
CytotoxicityCDC
Different from cell-mediated cytotoxicity ADCC
Formation of membrane attack complex MAC
bacteriolytic cell lysis
immune adhesion
Immobilize immune complex IC to red blood cells or platelets
Clear immune complexes
Antibodies do not have this function
Transported to liver cells or spleen cells for degradation
C3b
Modulate immune response
The relationship between complement and disease
Cytokines
Common characteristics of cytokines
Basic Features
Small molecular weight
Solubility
mostly glycoproteins
Not antigen specific
Mode of action on the body
autocrine
Paracrine
endocrine
Features
Pleiotropy
A cytokine can have different effects on different cells
overlap
Multiple cytokines can have similar effects
Synergy
One cytokine can enhance the effect of another factor
antagonistic
can inhibit another
networkedness
Multiple cytokines bind and control each other
Classification
Interleukin IL
leukocyte autocrine paracrine
There are 38 types in total
IL-2 stimulates T cell growth and differentiation; activates NK and macrophages
IL-3 induces differentiation of early hematopoietic progenitor cells
IL-4 promotes IgE switching
IL-5 enhances IL-4-induced class switching of B cells producing antibodies
IL-7 is secreted by bone marrow and thymic stromal cells
Plays a key role in immune cell differentiation and proliferation
IL-10 inhibits the synthesis of multiple cytokines
IL-1 is produced by monocytes-macrophages
IL-2346 is produced by T cells
IL-124 can promote T cell activation and proliferation
colony stimulating factor CSF
Stimulate the differentiation and proliferation of pluripotent stem cells and hematopoietic podocytes
Classification
IL-3
G-CSF
M-CSF
EPO erythropoietin
secreted by kidneys
Promote red blood cell differentiation and proliferation
TPO thrombopoietin
generate thrombus
IFN
Interfere with viral replication
Induces antiviral proteins that indirectly inhibit viral replication
Anti-cell proliferation
Antitumor
Immunomodulatory
tumor necrosis factor TNF family
Modulate immune response
Kill target cells
Directly induce tumor cell apoptosis
Mediates inflammation
growth factor GF
Promote cell growth and differentiation
TGFβ
secreted by tumor cells
promote tumor growth
Suppress cellular immunity
Chemokines
Mediates directional migration of immune cells
activate immune cells
Participate in inflammatory response
Classification
C subfamily
There is a cysteine C near the N-terminus
CC subfamily
CXC subfamily
An amino acid is inserted between two cysteines
IL-8
CX3C subfamily
Cytokine receptor CR
transmembrane factors
Composed of extracellular region, transmembrane region and cytoplasmic region
Classification
Type I CR family
hemopoietin receptor family
Type II CR family
interferon receptor family
tumor necrosis factor receptor family
Immunoglobulin superfamily
IL-17 receptor family
chemokine receptor family
shared chain
Each receptor is composed of 2 to 3 polypeptide chains
One of them is used to specifically bind cytokines
Cytokine binding subunit
Belongs to low affinity receptors
Another 1 or 2 are used to transduce signals
signal transduction subunit
often shared
Cytokine consensus chain
The two constitute high-affinity receptors
Cytokine receptor inhibitors
IL-1 natural inhibitor
IL-1Ra
Cytokine function
Regulate immune cell development and differentiation
central immune organ
Periphery
B cell Ig switch
Regulate the body's immune response
Anti-infective
Antibacterial effect
Antitumor
IFN-α/β activates NK cells to kill infected cells
induce apoptosis
IL-10, TGF-β exert immunosuppressive effects by directly inhibiting immune cell function or inducing regulatory T cells (Treg)
Th1 cells secrete IFN-γ, TNF-α, IL-2, etc.
Th2 cells secrete IL-456, 10, 13, etc.
IL-1, TNF-α, and IL-6 are endogenous pyrogens
Acts on the hypothalamus
Cause body fever
Stimulate hematopoiesis
leukocyte differentiation antigens and adhesion molecules
major histocompatibility complex MHC
definition
Gene group that determines graft compatibility
Classification
Category I
classic
ABC
non-classic
EFG
Category II
classic
DQ, DP, DR
DM, TAP, PSMB
Class III
genetic characteristics
Polymorphism
There are 2 or more alleles present at the locus
specific MHC
T cells recognize their own MHC
The MHC that T cells recognize is the MHC of CD8 or CD4 that matches itself.
B cells
Function
Antibody production mediates humoral immune response
antigen presentation
soluble antigen
Immunomodulatory
Secrete cytokines to regulate macrophages, NK cells DC, and T cell functions
differentiation and development
differentiation process
Progenitor B cells (pro-B)
Express Igα/β
heterodimer
Important markers of B cells
Mediates antigen-stimulated signaling
VDJ gene rearrangement completed during
Pre-B cells (pre-B)
Expresses pre-B cell receptor pre-BCR
Composed of μ chain (heavy chain) and replacement light chain
The heavy chain has been translated but the light chain has not yet rearranged
Inhibit homologous chromosomal gene rearrangements
ImmatureB
Expresses intact BCR mIgM
light chain translation
At this time, if cells are stimulated by antigen, they will undergo apoptosis.
develop immune tolerance
Mature B
Simultaneous expression of mIgD M on the surface
Unaffected by foreign antigens during the bone marrow phase
antigen-independent period
Found in the pleural cavity, peritoneal cavity, and intestinal lamina propria
differentiation mark
VDJ gene fragment rearrangement
Antigen recognition receptor diversity
portfolio diversity
Each gene segment contains a large number of genes
resulting in more types of BCR genes combined
Connect Diversity
Gene fragments have deletions and increased misalignments
Receptor editing
central immune tolerance
After the period from pre-B to immature B, mIgM binds to self-antigen, which will cause B cell apoptosis.
Clone clearing
At the same time, it causes down-regulation of mIgM expression.
Make B cells unresponsive to antigen stimulation
incapacitation
B cell status
survive
Light chains are rearranged
Receptor editing
Downregulation of mIgM expression
Disability
apoptosis
clone cleanup
B cell classification
according to activation stage
Naive B cells Bⁿ
Memory B cells Bᵐ
Effector B cells (plasma cells) AFC
Plasma cells cannot produce cytokines
by reaction type
B1 cells
Belongs to innate immune cells
Found in peritoneal cavity, pleural cavity, intestinal lamina propria
Act on early infection
Generate low affinity IgM
Express CD5
appear earlier
Mainly identifies TI-Ag
B2 cells
Generate high-affinity IgG
Classic B cells (follicular B cells)
B cell surface molecules
BCR
Composed of mIg and heterodimer
mIg binding antigen
Heterodimers conduct the first signal for antigen binding
Igα/β also known as CD79 a/b
The intracellular domain of CD79 is called ITAM
The first signal is transmitted after phosphorylation
Bind to native antigen
B cell coreceptor
CD19, 21, 81
CD19 is Epstein-Barr virus receptor
21 as the core
81 Stable co-receptor
Enhance first signal generation
costimulatory factor
CD40
second signaling molecule
Its ligand CD40L is expressed on activated T cells
The most important molecule for activating B cells
CD80,86
Also known as B7
Modulate T cell activation
B cell utilization promotes T cell proliferation
B cell surface markers
CD19, 20, IgGFC receptor
B cell classification
Divided according to activation stage
Initial B
Memory B
Effect B (Pulp)
by function
B1
Mediates humoral immunity
classic
B2
mediates innate immunity
Non-classic B
T cells
developmental stage
place
Thymic cortex to medulla
stage
ZuTpro-T
Pre-Tpre-T
immature T
Mature T
Initial T
Mature T that has not received antigen stimulation
Recognize antigen
Receiving presentation and activation in peripheral immune organs
differentiate into Tm Tc
In phase G₀
process
TCR gene rearrangement
DN cells
Before pro-T period
positive selection
Retain T with appropriate MHC-restricted affinity for exogenous antigens
DP cells to SP cells
negative selection
Low-affinity cells that retain endogenous antigen without MHC restriction
Acquire autoimmune tolerance
membrane molecule
TCR-CD3 complex
Function
TCR
Equivalent to antibody Fab segment
α/β is the majority
classical T cells
γ/δ minority
Non-classic T
Recognize antigen Recognize MHC molecules
CD3
conduct the first signal
coreceptor
Combined with APC
CD4
Binds to MHC I β₂ domain
Expressed in 60% of T cells
HIV receptor
CD8
Binds to MHC II α₃ domain
Molecules that promote the first signal of T cell activation
costimulatory molecule
positive stimulation
CD28 (ligand B7/CD80 86)
Promote T cell activation
Activate the initial T
Stimulate T cells to synthesize IL-2 and other CKs
Required when presenting antigen
negative stimulus
CTLA-4/CD152
Terminate T activation
Not expressed when T is at rest
ICOS (ligand ICOSL)
Depends on CD28
Promote T proliferation
Expressed in Th2
PD-1 (ligand PD-L1/2)
inhibit proliferation
IL-2, IFN-8γ
CD40L (corresponds to B cell CD40)
CD40L promotes APC activation
The importance of inducing B to respond again
CD40 promotes T activation
Interaction produces a second signal
mitogen receptor
FasL (ligand CD95L)
Subgroup classification
According to activation stage
InitialTn
EffectTe
memory
TCR type
αβT
adaptive immunity
γδT
No MHC restriction
Weak recognition ability
by function
T helper cell Th
Both express CD4
TCR coreceptor
Th0
naive T cells
activated by DC
Th1
secretion
IL-2
IFN-γ
TNF-α
pMHC is presented by macrophages to activated Th1
effect
Enhance cell-mediated immunity
Anti-infective
Activate CTL, NK and other proliferation and differentiation (IL-2 IFN-γ)
TNF-α promotes inflammatory response
Mediates type IV hypersensitivity reactions
exert cellular immunity
Th2
secretion
IL-4 5 6 10 13
B cells as targets for APC activation
exert humoral immunity
Th17
Regulate innate immunity
Cytotoxic T CTL
Both express CD8
Recognize endogenous antigenic peptide-MHC I
Directly kill target cells
Secrete perforin granzyme
Activated by endogenous antigens (tumor)
death receptor pathway
Fas (FasL), TNF-α (TNF)
Specific killing of tumor cells
Regulatory Tregs
Acts through direct cell contact
CD4⁺CD25⁺Foxp3⁺T cells
Have CD4
Inhibits CD48 T cell immune responses
Features
CK’s participation is required
Does not require exogenous antigen mediation
Antigen presenting cells APC
APC classification
Full-time APC
DC dendritic cells
maturation process
immature cells
Strong identification processing and weak presentation
No antigen stimulation
mature cells
Matures in peripheral immune organs as it circulates through the blood
Subtopic 2
Weak recognition processing and strong presentation
Normally in an immature state
Mononuclear/macrophages
B cells
concentrated antigen
Submission route
type I endogenous
protein ubiquitination
Enter proteasome for degradation
Type II exogenous
Degraded in endosomes and lysosomes
MHC class II compartment binds to pMHC
cross-submit
lipid antigen presentation
Branch topic 3
Branch topic 4
T cell mediated cellular immune response
stage
Recognize MHC-restricted antigens
activated T
produce cellular immunity
LFA-1 binds to APC
CD2
Expressed in 95% of mature T
activated T
Mediates non-specific binding of APC
Mediates non-specific binding to T
ICAM-1
LFA-3
B cell-mediated specific immune response
APC cells
professional cells
Dendritic Cells
Mononuclear/macrophages
B cells
Submission route
MHC class I pathway
MHC class II pathway