Antigen Presenting Flashcards
Proteins present on the surface of cells.
MHC molecules (Major Histocompatibility Complex )
Cells that process and display antigen to T-lymphocytes
APC (Antigen Presenting Cells)
T-cells that haven’t come in contact with antigen
ساذجة - Naïve T-Lymphocytes •
• Additional signals required for T-cells activatio
Co-stimulation and Co-stimulatory signals
Clonal expansion
Proliferation (increase in number) of a particular clone of lymphocyte (antigen specific lymphocyte)
Proteins released by several types of cells that act on other cells (adjacent –
paracrine, or distant-endocrine) Also called the cell messengers
Cytokines
Single lymphocyte that has…….. specificity and its own…….. cells.
antigenic
progeny
Organs where lymphocytes mature (primary) or accumulate (secondary)
Lymphoid organs
continuous movement of mature lymphocytes from – blood - peripheral lymphoid organs – lymph - blood
• Lymphocyte recirculation
continuous movement of mature lymphocytes from –………. - peripheral…………..–………. -………..
blood
lymphoid organs
lymph
blood
Clonal proliferation culminates in formation of effector cells / memory cells.
Lymphocyte differentiation
the lymphocytes acquire the ability to respond to the antigens (produce immune response)
Maturation
Maturation of the lymphocytes happens in the…………… like…….. gland and…………
1- central lymphoid organs.
2- thymus.
3- bone marrow .
so the precursors of lymphocytes differentiate into ………. And…….
b lymphocytes precursors and T lymphocytes precursors.
When maturation is done the cell then is called………………cell
immunocompetent
Once they mature, they inter the……………………., and they keep on circulating the body but they are yet to encounter the antigen therefore they are known as…………….
1- peripheral organs circulation
2- naive lymphocytes
When these naive lymphocytes encounter antigens they become activated and differentiated and proliferate and turn into effector cells. Proliferation of lymphocytes after antigen encounter is Known as
differentiation.
Differentiation
differentiation : When these naive lymphocytes…,…… antigens they become………… and………….. and proliferate and turn into….,….. cells. Proliferation of lymphocytes
encounter
activated
differentiated
effector
Lymphocytes which produce an immune response – antibody producing plasma cells from B-Lymphocytes and Cytotoxic Lymphocytes(CTL) and T-helper cells (TH cells) from T-lymphocytes.
Effector cells
Effector cells:
Lymphocytes which produce an immune response – antibody producing ………..from B-Lymphocytes and…………. and……….from T-lymphocytes
plasma cells
Cytotoxic Lymphocytes(CTL)
T-helper cells (TH cells
We have distinct lymphocyte clones each for a specific antigen . Since we have thousands of antigens we will also have for each of them ……………….clones.
specific distinct lymphocyte clones.
Some lymphocytes differentiates into long lived cells and are responsible for secondary immune response.
Memory cells
Total collection of lymphocyte specificities.
Lymphocyte repertoire
• Characteristics of adaptive IS
- Specificity (one lock for one key),
- Diversity (several locks for different keys),
- Clonal Expansion,
- Non-reactivity to Self (no locks for self keys).
lymphocyte will only……… it’s sought antigen.
recognize
Lymphocytes recognize antigens by………………..
antigen receptors on their surfaces
is where the antigen can bind to the lymphocyte.
Antigen receptor
peptide antigen bound to and displayed by MHC on APCs- by their T-
Cellً Receptor (TCR).
T-lymphocytes recognize
Unlike B lymphocytes, T lymphocytes cannot……… the antigen………
recognize
directly
the antigen must be………… to the T lymphocytes so they can recognize it
presented
The antigen is presented by the help of………………….. The antigen must be presented on the surface of APC and be bound to………. There are exceptions.
APC (antigen presenting cell)
MHC
These membrane bound antibodies are the receptors on B cells.
Recognize antigens by “membrane bound antibodies” on their surface.
B-lymphocytes
These membrane bound antibodies are the receptors on B cells.
Recognize antigens by “………..”on their surface.
membrane bound antibodies”
Recognize a variety of antigen such as
(proteins, polysaccharides, fats and nucleic acids).
Why does the immune system require specialized system of antigen presentation for effective immune responses?
a Antigenmayenterthroughanybodysite
b.Antigenspecificlymphocytehastocomeincontactwithits homologous antigen (1 in 1 million)—–should locate & react ASAP.
c. Different types of antigen may require different responses (antigens in the cytosol and nucleus vs. antigens in the vesicle).
d. SometimesISneedstoreacttothesamemicrobeindifferentways depending on its stage of infection.
Immune system has developed………….. system for capture and display of antigen.
highly specialized
Antigen is presented in the cytosol.
1-Cytosolic antigen .
Antigen is presented in the membrane bound the cycle.
2- vesicular antigen:
Molecules THAT play a critical role in antigen presentation to T-lymphocytes
MHC
Molecules THAT play a critical role in antigen presentation to T-lymphocytes
MHC molecules present on cell surface.
Antigen is bound with MHC molecule on cell surface.
Antigen- MHC complex displayed on surface of APC.
T-Lymphocytes recognize antigen only when it is displayed on surface of APC with MHC.
Each individual’s MHC is unique.
T-Lymphocytes recognize antigen only with MHC of same individual – MHC
restriction.
T-Lymphocytes recognize antigen by TCR.
T-Lymphocytes recognize antigen only when it is……………. on surface of APC with MHC
displayed
T-Lymphocytes recognize antigen by………………
TCR
B cell’s antigen binding receptor binds with the antigen…………
It produces antibody.
directly
1- T helper cell
Co-stimulator molecule:……..
CD4
T cytotoxic cell
Co-stimulator molecule:……..
CD8
Three steps of antigen presentation:
1- Capture
2- Process
3- Present
Function of Dendritic cells:
1- Capture antigen
2- Get activated
3- Migrate to L.N ( lymph node)
4- Present antigen to Lymphocytes
1-Capture
Binding of antigen to the dendritic cells in………… The dendritic cell will ingest the antigen through………………(macrophages will do it through phagocytosis also dendritic cell can make it through……………….).
lectin receptor mediated
receptor mediated endocytosis
phagocytosis
When the dendritic cells will get activate. What will happen to……………………. MHC.
Increase the production
The antigen has to be migrated to the …………through the ………………… The dendritic cells will express …………..(Chemokine receptor), it will express that after antigen…….. * It will attracted to move towards the lymph node.
lymph node
chemokine receptor.
CCR7
capture
Mature dendritic cell presenting antigen ( to ) …………
Naive T cell
In the blood the dendritic cells present in the spleen are responsible for…..
And why ?
antigen capturing presentation because spleen is the site where blood are filtered.
In the mucosal membrane in the skin, the antigen captured is by…………. cells located in the……….
dendritic
skin
HLA ادينا التفاصيل
(Human Leukocyte Antigens) is a synonym of MHC molecules.
Membrane proteins on APCs that display peptide antigen for
recognition by T- lymphocytes.
MHC molecules
2 types of MHC molecules –
Class I & II.
Both ofthe types of MHC made up of…………… chain but they are……….. different.
2 polypeptid
structurally