Unit 3 Adaptive Immunity Flashcards
This type of immunity helps if innate immunity isn’t enough to clear an infection. It is found in jawed or higher vertebrates.
Is it specific or non-specific for individual foreign molecules
Adaptive Immunity
Highly specific
What other important quality does the adaptive immunity have?
Memory of previous exposures, providing long term protection against re-exposure to the same pathogens
What type of cells are B cells and T cells?
Lymphocytes (like NK cells)
What are the names of receptors on T cells and B cells?
What are they specific for (what do they recognize on microbe?)
Do they work together?
TCR and BCR
Epitopes
Yes, on the same epitopes even
These are portions of antigens that are actually responded to
Epitopes
These receptors can only bind with epitope fragments, can’t bind when they’re still on the microbe, must be presented with that fragment
These can
TCR
BCR
This has an IgD antibody (binds IgD), IgD antibody becomes secreted more frequently after it attaches initially
BCR
Only _______ can bind antigens, which are on the surface of pathogens
The smallest part of an antigen that can be recognized is the __, its a clustering of AAs
Is there only one epitope or multiple on an antigen?
The B cell reacts with an epitope with a certain antibody, and that antibody is ultimately secreted
Immune receptors
Epitope
Multiple different epitopes, each capable of stimulating a response
Where do B cells and T cells originate?
T cells migrate in a still immature stage to the ___ for further development
What do T cells learn in this place?
The bone marrow
Thymus Gland
Tolerance of body cell proteins
The bone marrow and thymus are ____ ____ organs
Generative Lymphoid Organs
During development, gene rearrangements produce a very large number of ____ and ____ to increase the chances of a reaction against pathogens, they are formed before exposure to pathogens
TCRs and BCRs
Also very diverse between different people, beneficial to our species
Once mature, lymphocytes are expelled into the peripheral blood stream as mature, _____ lymphocytes
These cells migrate through ____ tissues distributed around the body, ready to respond to threats
naive
Lymphoid Tissues
This is the second role of lymphocytes, other than immunity
This is the third role of them in the digestive system, they absorb lipids from foods we eat
Absorbs excess tissue fluids (like in elephantitis)
Lacteals
What causes lymphocytes to move around?
Muscle contraction (bodily movement)
What are the primary lymphoid organs
Bone marrow and thymus
What does ‘naive’ lymphocytes mean?
Not yet encountered epitope receptor they are specific for
Tonsils, spleen, lymph nodes, appendix, tespeyer’s patches areissues (have many lymphocy
Secondary Lymphoid Tissues
This is a response after the primary response in adaptive immunity
Anamnestic (booster, memory)
What is the main difference between the primary and anamnestic response?
The primary response produces ___ lymphocytes as a result
Days following response, 7-14 days for primary
Memory lymphocytes (Memory B and T cells)
One of the important players of the adaptive immune response, multiple types are involved
They are involved with cell mediated side of adaptive immunity (aka destroy infected body cell, intracellular colonizer), B cells aren’t involved
They can also be involved in humoral response (extracellular), aka antibody response
T cells
What are the three things that activation of T cells requires
Antigen Presentation
Cell signaling
Production of stimulatory responses
Activated T cells expand and differentiate into their ___ cells or ____ cells
Effector, Memory
aka clones
What are the three types of antigen presenting cells (like to T cells)
Macrophages
Dendritic Cells
B cells
Cell signaling, required for activation of T cells, involves what molecules?
Cytokines
These type of differentiated T cells work immediately
These work later on, are in reserve for later for fast response
Effector
Memory cells
A naive cell must interact with ____ to become dactivate
This triggers…
Antigen presenting cell
Differentiation into effector and memory cells (clonal expansion)
T cell activation requires binding of the TCR with the specific peptide presented on ____ molecules of APCs
Can APCs be body cells?
MHC molecules (a presentation complex with epitope)
Yes if they are infected by an intracellular colonizer, presents fragments growing inside of it
These are special groups of APCs for extracellular colonizers
Macrophage
Dendritic cell
B cell
T cells are very specific because they are produced in the ___ and mature in the _____
They are screened to avoid excessive ____
Good T cells with anti-foreign molecule TCRs are released into the
Bone Marrow, Thymus
Self-reactivity
Peripheral blood stream
Does one T cell have multiple receptor types or just many of one receptor?
Many of one receptor
How can one APCsactivate multiple different types of T cells?
They present multiple different epitope fragments with all of its MHCs
Co receptors on T cells also must correctly interact with the MHC molecule. It helps provide the correct ______ signal to the correct type of T cell
This type interacts with MHC class II
This type interacts with MHC class I
Activation
CD4 (helper T)
CD8 (killer T ,or cytotoxic T, Tc)
There are two types of helper Ts (CD4 cells)
This type stimulates cellular immune responses, good for intracellular colonizers
This type stimulates humoral (antibody) responses
TH1
TH2
So a T cell has a TCR and a co-receptor, the TCR binds to the ___ and the coreceptor binds to the ____
Epitope
MHC complex
Which cells have MHC II complexes?
Macrophages, Dendritic cells, B cells
Establishing memory of previous exposure is a hallmark of ___ immunity
_____ cells differentiate during initial adaptive immune responses. They are long lived, produce a faster and more rigorous response when the same antigen is encountered again, and the speed of the 2nd, 3rd, 4th, response can even prevent a repeat infection from occurring
Adaptive
Memory cells
These are the action cells, which are short lived and armed with direct immune functions
Effector cells
In T cells, effector form depends on co receptors.
In CD4+ T cells, secretion of large amounts of _____ enhance and direct actions of OTHER immune cells
In CD8+ T cells, cytotoxic killing of infected cells by release of ______ near contacted target the cell, initiating apoptosis. Part of cellular immune response
Cytokines
Granzymes/perforin (similar to NK cells)
In CD4 T cells, an antigen presenting cell, could be a body cell, is binded (twice, once epitope once MHC) by the T cell. The activated CD4 T cell secretes ____ and expression its receptor for autostimulation of that molecule
Clonal expansion and differentiation produces a population of memory and effector TH cells
Interleukin-2 (IL-2)
This term means the cell releases a chemical which binds back to itself repeatedly, it actually makes more receptors for the chemical as well. Afterwards it divides and differentiation occurs
Autostimulation
In intracellular antigens and the endogenous pathway, ___ t cells are used
CD8 T cells (Killer T cells)
Killer T cells recognize targets by their presentation of antigen epitope fragments on ______
Killing is achieved by T cell release of ______, inducing apoptosis in a target
MHC 1
Perforin/Granzyme
So in CD8 T cells, antigen presentation and binding by the CD8 T cell occurs to the dendritic cell or macrophage
The activated CD8 cell expresses a ____ receptor that binds ____ produced from TH cells
Clonal expansion and diffrentiation produces a population of memory and effector Tc cells
interleukin-2 receptor
IL-2
Which cells communicate with the activated Killer T cells? TH1 or TH2? The CD8 T cells will then divide
TH1 helper T cell
The cytotoxic T cell that was made from clonal expansion recognizes infected body cells by binding to the…
Which binds first? TCR or CD8 co receptor?
Do they both bind the MHC 1?
What occurs to kill the body cell?
The cell contents are degraded by
MHC 1 peptide complex with the epitope derived from the infecting microbe
TCR
Yes
Degranulation
Phagocytes
These are phagocytic cells that are very efficient at antigen reuptake, and thereby function as APCs. They are named for many long cytoplasmic extensions that resemble nerve dendrites
What cells are they made from?
They are formed where?
Dendritic cells
Monocytes
Bone Marrow
The innate functions of these cells include phagocytosis and intracellular killing
Macrophages
The APC functions of macrophages include presentations to memory ______ and ________ T cell subsets in secondary responses
What else can they do?
CD4 and CD8
Determine the course of CD4 T-cell differentiation into particular subsets
These cells are critical for adaptive immunity.
They produce ______
Also present MHC ____ peptide on their surface to CD4 Tcells
B cell
antibody
MHC II
What is the B cell receptor?
B cell receptors trap foreign _____
It is ingested and broken into fragments. They are loaded onto MHC class ____ molecules
Presentation to CD4 T cells occurs on TCR, causing them to secrete _____
IgD
antigen
II
cytokines
These help the B cell to differentiate into an antibody secreting plasma cell or a memory B cell
Cytokines
Most B cells need the help of T cell ____ to become fully activated, and they can’t get it without presenting antigens
Cytokines
Cytokine secretion by Th cells is required for activities of ___ cells and ____ cells
But antibodies from them won’t directly help kill or directly kill them, respectively.
Because of the different immunity needs, there are two broad types of responses. What are they?
B cells and Tc cells
Humoral Immunity
Cell-mediated Immunity
This type of immune response is good against extracellular pathogens
Humoral
This type of immune response is good against intracellular pathogens
Cell-mediated
Th1 and Th2 are helper T cells that are a common link between the two types of ____ immunity
Different subsets of helper T cells help in different ways by releasing different sets of ____
Which MHC do helper Ts present?
Adaptive
Cytokines
MHC II (both CD4 cells)
Which Th cell is involved in cellular immune responses?
Which in humoral?
TH1
TH2
What are the 3 responses produced by TH1 cells
Specific inflammatory response
Phagocytic Cell (macrophages/neutrophils)
Activate Killer T (CD8)
Fast onset inflammation is caused by
Slow onset is caused by
Histamine (innate)
TH1
What does TH2 talk to to stimulate the production of antibodies?
What is the APC in this instance?
B cells
B cell as well. After talking to TH2 it differentiates into plasma cell to be able to produce antibodies
Which cytokines can suppress the activity of TH2 cells?
What cytokines suppress the activity of TH1 cells?
TNFα, IFN-γ
IL-10 & 13
Which cell is responsible for inflammation that ends up damaging our own body cells? TH1 or TH2?
So which cytokine suppresses the inflammatory response
TH1
IL-10 & 13
Recall that our best understanding of how B cells produce antibodies is in response to protein antigens from foreign sources
These responses usually require ____ help from helper T cells
Cytokine help from helper T cells
To produce antigen, B cells must first bind to the foreign antigen through the BCR, then ingest it and process it. Presentation of the antigenic peptide to the TCR on the helper T cell solicits the ____ help
Which cytokines do this?
The B cell multiplies, differentiating into antibody secreting plasma cells and _______ cells.
Cytokine help
IL-4 and IL-6
Memory cells
In B cell responses to protein antigens, primary responses typically produce a modest amount of antibody after ______ days
Secondary responses shift to much faster and larger scale antibody production
Does the B cell retain the ability to respond to different antigens?
7-14 days
Yes
Plasma cells can secrete 2100+ antibodies per
Are plasma cells able to divide anymore? What is the term to describe this?
What happens to the plasma cells in about 2 days?
Do the antibodies last longer?
second
No. Terminally differentiated.
Apoptosis
Yes, for weeks even
Antibody production by plasma cells in specific/nonspecific
All antibodies from on eplasma cell are identical and will bind only to a single ___ on an antigen
RVery specific
Epitope
Recall that a single antigen may have many ____ - so many different plasma cells can be formed, each with a different specificity
Epitopes
This antibody (glycoprotein) has 2 heavy chains and 2 light chains forming a Y shaped structure
What type of bonds exist within and between chains?
IgG
Disulfide Bonds
The two arms of the Y in IgG form what?
The bottom of the Y forms what?
Antibody binding fragments (Fab) aka where epitope binds
Region that self receptors bind to
IgG has variable and constant regions on the heavy and light chains. Variable regions can be different between different IgG antibodies
!
The variable regions bind unique epitopes while the constant regions bind the same between different IgGs
!
A region of IgG made of the constant heavy chain and another constant heavy chain
Fc region
This region of IgG binds complement and Fc receptors on phagocytes to allow the white blood cell to conduct phagocytosis
The IgG acts as what?
Fc region
Opsonization factor
This antibody is the main part of the B cell receptor, its not released to do a job elsewhere.
IgD
The use of diferent C-region gene segments leads to different classes of antibodies. Each class has slightly different structures and functions in immune responses. This phenomena is called
Antibody class switching (aka phenotype switching)
Which antibody is always the first antibody in a primary response?
Why is IgM made first?
The complex class switching process can change the type to make the most efficient response to make what antibodies?
pentomeric IgM (p IgM)
5 IgM monomers means there are 10 binding sites
IgA,IgE, IgG
What are the same between the IgA, IgE, and IgE
What is different?
Variable light variable heavy chains (they must bind to the same antigen that triggered IgM production in the 1st place)
The constant region is different
This class of antibody is a dimer, found in tears, milk saliva, aka mucosal membranes. Also called secretory antibody.
How many binding sites, then?
IgA
Dimer = 4 binding sites
First type most pathogens encounter because its in the mucosal membrane…
IgA
This is the most abundant antibody because of the amount of surface area on mucosal membranes
IgA
These are monomer antibodies associated with eosinophils and allergic reactions.
IgE
IgEs bind to what two cell types, causing degranulation and inflammation?
What is the chemical released that causes inflammation?
Basophils and mast cells
Histamine
This antibody is a monomer, and is the most present antibody in the serum (in our blood) to activate complement cascade.
IgG
This monomer antibody can cross the placenta because its small to protect the baby.
IgG
The functions of antibodies
Blocks binding of pathogens/toxins on host cells (binding to the pathogen)
Fixes complement to bacterial structures for lysis
Opsonization
Agglutination
Activations eosinophils, basophils, and mast cells by providing an exposed FC region for cells to bind to
This is clumping of antigen caused by antibodies increasing phagocytosis
Agglutination
NKs respond to MHC 1 missing
NK T cell responds to epitopes presented to them on MHC 1, more specific
Both are lymphocytes
!
___ immunity can cause damage to our structures if it is inappropriately of excessively damaged
Adaptive
Th1 cells and Th2 ——-> MHC II
CD8 aka killer T’s have ———> MHC I
!
