Adaptive Immunity Flashcards
Adaptive immunity is what line of defence
3rd line
Between innate (inflamatory) response and adaptive response which is faster?
Innate- activation is immediate post tissue damage ([Mast cell, Histamine and other Cytokine responses]
Vascular events and s/s of inflammation.
Adaptive response is slower- [7-14 days] and induced by
infection/damage in response to the innate immunity
via lymphocytes and antibodies
what is the difference in immune response between innate and adaptive immune response
Innate- rxn similar irrespective of cause of damage and is non specific
Adaptive immunity: response is specific to an infecting microbe/pathogen/antigen
what happens to produces mediators of immune respones in both innate and adaptive response
Innate immunity: The residual mediators of inflammation can damage surrounding healthy tissue and need to be removed
to support healing
Adaptive immunity: the products of adaptive immunity are long-lived and systemic providing long-term immune protection
[memory response] against the specific pathogen
What happens in case of reinfection in innate and adaptive immune response
Innate: Recurrent injury/infection this response is identical to
the initial injury/infection
Adaptive:
Re-infection triggers very specific
lymphocytes/antibodies immediately assuring faster
and longer-term protection/management of
pathogen
Naive T and B cells are made where.
Thymus- for T cells
Bone marrow for B cells
What is the process of Humoral immunity
Antibody mediated
The process where by T cell and B cells under go differentiation to be come immunocompetent T and B cell is called what?
Generation of Clonal diversity
Are naive T cells and B cells specific?
No, they have never encountered an antigen
What is Clonal selection?
It’s a process of selection, proliferation and differentiation of individual T and B cells with receptors for specific antigen
Where are the B and T cells found circulating in the body
T cell mostly circulating in the blood
B cells 80% are located the lymphatics where they await invading organisms
What triggers B cells to start the humoral immunity
Free floating antigens
When lymphoid stem cells enter the thymus they differentiate into what
T lymphocyte
ie T cells derived from thymus
When lymphoid cells enter the bone marrow they differentiate into what
B lymphocytes
ie B cells
Clonal Diversity is what?
Process by which B and T cells establish their diversity of antigen receptor
When immunocompitent B cells and T cells enter the blood and lymphatic where do they migrate to?
Secondary lymphoid organs ( lymph nodes spleen)
What initiate Clonal selection
Foreign antigen
What happens after Clonal selection?
Proliferation and deffentistion resulting in cellular or humoral immunity
What mediate cellular immunity
T cytotoxic cells
T regulatory cells
Memeory T cell
Can respond quickly to 2nd challenge with the same antigen
After differentiation, B cells into specialized cells, develop into what?
Plasma cells that becomes factory for antibody production
Antibody circulating in the blood and defend against extracellular microbes and toxin is called what?
Humoral immunity
Clonal selection occurs where in the body?
Peripheral
Adenoids
Tonsil
Lymph nodes
Lymphatic vessels
Sleep
Payer patches (ileum only)
All nucleated cells express self antigen know as what
MHC 1
Why Phagocytosis neutrophils breakdown antigen into what?
Free radical reaction (oxidative burst) or exocytosis - expel the elements into extracellular space called FREE ANTIGEN
Macrophages/dendritic cells breakdown elements and expose the antigen on the membrane via what?
MHC2
Where is complement produce? And what are the 3 cascades?
Complement produced in liver in inactive form
Complement cascades
1. Classical antibody activated C1-C9 producing C3a and C5a
2. Alternate - direct binging or antigen protein via C3b trigger cascade and C3a and C5a
3. Lectin pathway - via pathogens surface coat
What are the function of the complement pathways
For direct lysis of bacteria
Opsionization of C3b
Enhance inflammation C3a &C5a
What is the process of Humoral immunity
Macrophage [presenting antigen [pieces of the organism] on their surface carried by major
histocompatibility complex type 2 [MHC 2]
- Neutrophils exocytosis their antigens into the extracellular fluid [called FREE ANTIGENS]
- Both move into the lymphatic system in which there are many “naïve” B and T-lymphocytes [with
multiple receptors] - B-lymphocyte and T-lymphocyte process from “naïve” to “activated”
- How they interact with each other to produce differentiated B-memory cells and Plasma cells
What are the ways plasma screated antibodies kill pathogen?
- neutralization
- Lysis
- opsionization
- precipitation
- agglutination
Process of inactivating or blocking the binding of antigens to receptors is known as what?
neutralization
clumping insoluble particles that are in suspension is known as what?
Agglutination
making a soluble antigen into an insoluble precipitate is known as what?
Precipitation
precipitation during humoral immune response can trigger what?
opsonization, and is linked to hypersensitivity response /autoimmunity
Agglutination during humoral immune response is linked to what condition?
hypersensitivity/alloimmunity
opsonization
Indirectly via complement cascade/system or
Directly via macrophage stimulation
Binding of naive B cell lymphocytes to free floating antigen is by random chance
True or false
True
What’s the process of humoral immunity?
Binding of naive B cells to free antigen receptor result in biochemical reaction which changes naive B cells to what?
Mature/activated antigen specific B cells
activated B lymphocyte undergo phagocytosis, engulf antigen attached to the receptor on its cytoplasmic space in a what
endosome
When is B cell considered activated?
When the nucleolus of B lymphocyte chromosome ##6 identifies and attach to the receptor (in endosome) and create MHC2 that present antigen on surface of B cell, creating an antigen precenting cell
MCH 2 with antigen presents the antigen to what cell?
naive T lymphocyte also known as
T helper cells
What is specific recombination
the T-cell can shuffle the receptors on the surface of the cell to find one that specifically fits the
antigen being presented and then attaches itsef.
True or false
The T-cell receptor [TCR] are specific to types of antigens
True
What are the 5 proteins on naive T lymphocutes
- T cell receptor
- Cluster differnetiation 4 (CD4)
- Cluster Differentiation 3 (CD3)
- Cluster differentiation28 (CD 28)
- Interleukin 1. (IL1)
What is the function of T cell receptor (TCR)
bind directly onto the antigen being presented
Whats the function of CD4?
. Cluster Differentiation 4 (CD4) binds to the MHC2 presenting molecule on the macrophage,
Whats the function of CD3
Cluster Differentiation 3 (CD3) which is attached and activated by the CD4 binding to the macrophage and
MHC2 binding to the antigen
whats the function of CD 28
Cluster Differentiation 28 (CD 28) that binds to macrophage B7 molecule found on surface [acts to anchor] and nucleus signaling system
What is the function of IL1
Macrophage release Interleukin 1 (IL1) when transporting an antigen, the T-cell has a receptor that captures
this Interleukin 1 and uses it for 3rd signaling
What is primary signalling
The MHC2 antigen and CD4/macrophage are attached to the “naïve” T-lymphocyte [helper cell] this triggers
the CD3 signals to the nucleus
Whats is secondary (co-stimulation) signaling:
Secondary [co-stimulation] signaling: CD28 attached to macrophage B7 and this signals to the nucleus
What is 3rd (co-stimulation) signaling
When IL1 from the macrophage binds to the T-cell receptors for IL1 this signals to the nucleus
also
Nuclues stimulation causes T cells to release what key substances
- Humoral (Th2 cells)
- Cell mediated (Th1 cells)
- Suppress the immune responses (T regulatory cells or self turn off switch)
- Th17 cells part of the inflammatory process
Humoral [Th2 cells]
- IL 4 which stimulates the T-helper cell to turn into Th2 cells [this mature activated cell continues to produce more IL2 IL4 and IL5]
- IL 5 which stimulates differentiation of activated B-cells
- IL 6 which stimulate differentiated plasma cells to carry out their antibody work
Cell-mediated Immunity [Th1 cells]
IL-12 which produces Th1 cells and stimulates TNF beta, IL 2 and IFN [interferons]
Suppress the Immune Response [T regulatory cells or self turn off switch]
IL 2 which continues to stimulate the T-helper cell [autocrine “self stimulation”] to help proliferation and replication into Th2 cells
Activated T helper 2 cell producing IL4 stimulate activated B lymphocyte (activated B- cell) to start excessive what
CLONAL EXPANSION
Proliferation produce new B cells that have surface MHC2 receptor and IgD specific for what antigen?
Antigen captured when it was naive B cell
After expansion, IL5 take the proliferated activated B cells (with specific receptors on their surface for the foreign antigen) and stimulate them to undergo what
DIFFERENCIATION
Differenciation result in what
Memory B cells ( specific for the antigen) and
Plasma cells [note: IL5 with IL6 will stimulate the plasma cell to secrete very specific
antibodies into the blood for the antigen]
antibody floating in plasma can do the following
- neutralization reaction
- Lysis
- Direct or indirect Opsionization
- Precipitation reaction
- Agglutination reaction
Antibodies binds to all the receptors on the pathogen surface [blocking its ability to bind to human cells] causing
NEUTRALIZATION REACTION
Antibody binds to a receptor on the pathogen surface triggering the COMPLEMENT CASCADE SYSTEM that were able to produce several C proteins which produce a membrane attack
complex [MAC] which attack the membrane of the bacteria resulting in what?
LYSIS REACTION of the bacterial cells
Indirectly: Antibody bind directly to the antigen/pathogens surface triggers the COMPLEMENT CASCADE
SYSTEM to have produce C-proteins thus C3b receptors that triggers the macrophage [have C3b receptors] and phagocytosis/eat the antigen/pathogen
OPSONIZATION
Directly: Antibodies bind directly to the antigen/pathogen surface and just directly triggers macrophage to
phagocytosis/eat the antigen/pathogen
OPSONIZATION
Antibodies binds to a free antigen causing
PRECIPITATION REACTION which enhance opsonization
*
Over reaction of precipitation reactions triggers hypersensitivity, precipitate deposits into normal tissue trigger what type of hypersensitivity
Type 3 hypersensitivity, autoimmunity reaction e.g Systemic lupus erythromatosus
Incompatible blood [RBC] [transfusion or maternal/fetal incompatibility] antibodies that bind to these RBC
antigens on the surface of the incompatible blood [see them as foreign bodies] to attack them
AGGLUTINATION REACTION
What are the functions of antibody
Direct
- Neutralization
- Agglutination [alloimmunity]
- Precipitation [autoimmunity]
Indirect
- Inflammation
- Phagocytosis
- Complement [Lysis reaction,
Opsonization)
Cell mediated immunity means
- Cell mediated antigen/problems inside the cell or endogenous protein
- Viral proteins/Cancerous proteins invaded cell in which the cell itself is being damaged – non-reversible
- Because it is not reversible then T-cytotoxic cells must kill the infected cell itself
What are the 2 main surface protein of T cytotoxic cells
Protein cluster differentiation 8 CD8 which recognizes MHC1 molecule receptor and bind to it
Has T receptor (TCR) that recognizes self antigen on thr MHC1 that will bind to the self antigen ( this can trigger autoimmune response and damage own tissue cells)
What are the 2 substances produced by T cells which help in killing pathogens
- Perforins which puncture holes in cellular membrane of infected cells
- Granzymes moves into these puntured holes and goes into the nucleus of infected cells to trigger pro-apoptosis gene
Are natural killer cells part of adaptive immunity
No
What’s the difference between cytotoxic T cells and natural killer cells
Natural killer cells function like the T cytotoxic cells but outside the adaptive immunity
What are the 3 ways natural killer cells kill
- If no MHC1 molecule on the cell surface (ie lack of self antigens)
- MICA- polymorphic protein that induces stess, damage or transformation to a cell which acts as kill me signal for natural killer cells
- IgG on the surface of a pathogen infected cell
NK cells kills by
Releasing releasing perforins (puncture holes in cell membrane),
granzymes (enter holes and trigger nucleus to release pro apoptosis gene
Pro apoptosis gene BAX pulls out thr BCL2 location in the membranes of mitochondria resulting in destruction of cell inside out
What is active immunity
Developing own immunity - lymphocytes and antibodies to antigen
Natural infection by pathogen
Vaccine (live or attenuated)
Cancer
Allergic desensitization
Passive immunity
When preformed antibodies or lymphocytes are administered to individuals
Immunoglobulin vaccine (Rabies)
Rh immunoglobulin vaccine (fetal maternal incompactabke blood or transfusion incompactabke blood
New born/maternal Ab shift (IgG passing through placenta)
