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116 Cards in this Set

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  • Back
What are the three types of granules contained in PMN?
1) Primary
2) Secondary
3) Gelatinase
When do the primary granules in neutrophils work? What form are they stored in? What is stored in them?
Work during phagocytosis - they are the first to be released. Stored in active form. Lysozyme, defensins, collagenase, cathepsin B (inhibits peptidoglycan synthesis), myeloperoxidase.
What form are secondary granules stored in? What kind of enzyme secretion is it? What do they contain?
Stored in inactive form, regulated secretion. Contains receptors for chemotactic factors that can be incorporated into the plasma membrane, lysozyme, collagenase, lactoferrin.
What are the four antibacterial superpowers in the oxidative burst?
O2- (superoxide), H2O2 (hydrogen peroxide), .OH (hydroxile), HOCl-(bleach)
What catalyzes O2 to H202?
Superoxide dismutase
What catalyzes H202 to H20
Catalase
What catalyzes .OH to HOCl-
Myeloperoxidase
What is the function of monocytes and macrophages? What do they produce? How do they play are part in both innate and specific immunity?
Monocytes and macrophages are phagocytes. They produce cytokines. Innate - phagocytes. Specific - present antigen to T cell!
What kind of immunity do natural killer cells provide?
1) Anti-viral immunity
2) Tumor immunity
If natural killer cells have receptors, why are they part of the innate immune system and not the specific?
They have receptors, but NO ANTIGEN RECEPTORS.
What are microbial molecular arrays? Are they innate or specific immunity? List some examples.
Shared substances among groups of organisms. In innate immunity because they can be shared by many different types of organisms.

LPS - gram negative bacteria
Lipotechoic acid - gram positive bacteria
Glycolipids - mycobacteria
dsRNA - viruses
What are the microbial molecular arrays for:

1) Gram - bacteria
2) Gram + bacteria
3) Mycobacteria
4) Viruses
1) Gram - = LPS
2) Gram + = lipotechoic acid
3) Glycolipids = mycobacteria
4) Viruses = dsRNA
What do toll like receptors recognize?
Recognize a wide array of microbial ligands (LPS, peptidoglycan, flagellan)
After LPS is released by a dying bacterium, what does the immune system do?
LPS binding protein binds LPS, brings it to the toll-like receptor 4, which activates the cell it's on (ie macrophage)
What are toll-like receptors on? What do they do?
On cells like macrophages, which will get rid of LPS. Activates the cell.
What is a hapten? How does it work?
An antigen that is NOT an immunogen. It is too small to be recognized by the immune system to provoke an immune response.

Alone, no immune response, but when combined with another molecule, antibodies are produced against the combined molecules and will react with both the hapten and carrier protein.
What is an epitope?
The physical part of the antigen that is directly recognized by the paratope (antigen binding portion) of the antibody.
Pathogens can have a bunch of different ____ which are all recognized by their own individual antigen.
Epitope.
What is a paratope?
The antigen binding site portion of the antibody.
What is a monoclonal antibody derived from? What do monoclonal antibodies react to? Where are they made? What are they useful for? What are they produced by in humans?
Derived from a single clone of plasma cells, they all react to the same antigen. They're made in labs, useful for diag procedures. Made in humans when they are produced by plasma cell tumors (myelomas).
What are myelomas and what do they produce?
Plasma cell tumors that produce monoclonal antibodies.
What are polyclonal antibodies derived from? What do they recognize?
Derived from many clones of plasma cells, antibodies that recognize multiple epitopes. This is the normal immune response.
What is another name for antibody?
Immunoglobulin.
What is the makeup of an antibody (ie chains?)
2 identical heavy chains, 2 identical light chains, joined at the hinge region.
How many AAs make up a domain in an antibody? What is the domain stabilized by?
110 amino acids long, stabilized by intrachain disulfide bond.
In what region of the antibody is a paratope located?
Variable region.
How many variable and constant regions does a light chain have?
1 variable, 1 constant.
How many variable and constant regions does a heavy chain have?
1 variable, 3 constant.
An antibody's hypervariable is what makes the antibody unique UNLESS...
The antibody comes from the same clone as another antibody.
What is the idiotype of the antibody?
The hypervariable region. It's what makes it unique.
What important site does the hypervariable region make up on the antibody?
Paratope.
Describe the makeup of an idiotype (variable, constant regions)
Two variable regions - variable region of the heavy chain, variable region of the light chain.
What are the two separate fragments on the antibody?
Fab - Fragment antigen binding
Fc - Fragment crystallizable
Where on the antibody does the globular head of C1 bind?
CH2.
Where on the antibody does the receptor on phagocytes bind?
CH3.
What is the function of the CH2 on the antibody?
It's the place where the globular head of C1 binds.
What is the function of the CH3 on the antibody?
It's the place where the Fc receptor on the phagocytic cell binds.
What is the job of the hinge region in an antibody?
It confers flexibility.
What are the two main functions of the Fc fragment on the antibody?
1. Opsonization - CH3 binds to Fc receptor on phagocytic cell
2. C-fixation ((C1 globular heads bind to CH2 region of Fc)
Ig class is determined by...
the heavy chain.
What are the five isotypes of Igs, and how many subclasses of chains does each have?
G,A,M,E,D. G has 4 subclasses (gamma 1, gamma 2, gamma 3, gamma 4), alpha has two subclasses (alpha 1, alpha 2)
What are the two types of light chains?
Kappa and lambda.
Describe the main characteristics of IgG:

1) Predominant in?
2) What is its function?
3) What is a unique feature?
1) It's the predominant immunoglobulin in serum (75% of serum Igs)
2) Binds complement IgG1, IgG3
3) Actively transported across the human placenta - it is the ONLY IgG transported.
Describe the features of IgM:

1) When is it produced in a reaction?
2) Size?
3) What is it the most efficient at?
1) First produced in immune response
2) Largest
3) Most efficient at agglutinating and C-fixing antibody.
Describe the features of IgA:
1) What is it predominant in?
2) What is a unique feature?
Predominant in secretions. MOST ABUNDANT ANTIBODY OVERALL, GREATEST SYNTHESIS.
What is IgE involved in?
Allergies, anti-worms.
Where is IgD found?
Membrane bound in naive B cells (with IgM).
What Ig is predominant in serum? How much?
IgG, 75%
What Ig fixes complement factors? Which ones?
IgG - IgG1, IgG3
What Ig is actively transported across the human placenta?
IgG.
Which Ig is produced first in the immune response?
IgM.
What is the largest Ig?
IgM.
Which Ig is the most efficient at agglutinating and C-fixing antibody?
IgM.
Which Ig is predominant in secretions (ie mucosa)?
IgA
Which Ig is the most abundant antibody overall?
IgA
Which Ig is involved in allergies and anti-worm immunity?
IgE
Describe the structure of IgG. Which subtype is different and why?
Monomer with 2 antigen binding sites.IgG3 is different - has a huge hinge region, one of the most flexible antibodies there is.
Describe the structure of IgM.
Pentamer with 10 theoretical antigen binding sites (usually only 6 bind).

- Extra CH domain
- J chain, which is responsible for holding the five units together.
Does serum or secretion? What does it look like in secretion?
both. Found in secretions but it's less common than IgA in secretions.

Pentamer + J chain + secretory piece
Which Ig is produced first in the immune response?
IgM.
What is the largest Ig?
IgM.
Which Ig is the most efficient at agglutinating and C-fixing antibody?
IgM.
Which Ig is predominant in secretions (ie mucosa)?
IgA
Which Ig is the most abundant antibody overall?
IgA
Which Ig is involved in allergies and anti-worm immunity?
IgE
What Ig is found membrane bound in naive B cells, along with IgM?
IgD
Describe the structure of IgG. Which subtype is different and why?
Monomer with 2 antigen binding sites.IgG3 is different - has a huge hinge region, one of the most flexible antibodies there is.
Describe the structure of IgM.
Pentamer with 10 theoretical antigen binding sites (usually only 6 bind).

- Extra CH domain
- J chain, which is responsible for holding the five units together.
Does IgM exist in serums or secretions? What does it look like in secretion?
both. Found in secretions but it's less common than IgA in secretions.

Pentamer + J chain + secretory piece
Why doesn't free IgM fix complement?
Because complement only binds to antigen-antibody complex.
What kind of conformation does IgM undergo after binding antigen?
Crab. It's now efficient at fixing complement.
Describe the structure of serum IgA.
Describe the structure of secretory IgA.
Monomer with 2 antigen binding sites.

Secretory - Dimer with 4 antigen binding sites, J chain (plasma cell origin), secretory piece (epithelial cell origin)
J chains are found in which Igs?
Secretory version of IgA and IgM.
Describe how the secretory unit gets onto secreted IgA and IgM.
Ig crosses mucosal epitheliums. Binds to poly-Ig receptor, which stimulates the whole complex to be endocytosed into cell. Inside cell, enzyme comes along and separates Ig from receptor, but leaves a bit of the receptor stuck to the Ig (this is the secretory component).
What cell makes the secretory component on a secreted Ig?
Epithelial cell.
What cell makes the J chain in secreted IgM and IgA?
Plasma cell.
Describe the structure of IgE. What does IgE bind to?
Monomer with 2 binding sites, extra CH domain.

Binds to FcE receptors on basophils and mast cells (allergies)
What are the 3 main functions of an antibody? Can an antibody directly kill a cell?
1) Opsonization
2) Neutralization of viruses and toxins
3) Complement mediated cell-lysis

CANNOT directly kill a cell.
How do antibodies neutralize viruses?
Bind to viruses and prevent them from getting into the cell to replicate.
What kind of bonds exist between antigen and antibody? What does this account for?
Non-covalent bonds - weak. (Hydrogen, electrostatic, hydrophobic, van der waals). Accounts for reversible binding.
What is the definition of affinity?
The strength of non-covalent interactions between a single antigen-binding site on an antibody and a single epitope on an antigen
What is the definition of avidity? What does avidity compensate for?
The strength of the reaction between a complex antigen and a mixture of antibodies directed against different epitopes of that antigen. It compensates for low affinity.
What is an example of an IgG with low affinity and high avidity?
IgM - pentameric.
Why is it more beneficial to have a polyclonal antibody response?
Because it means high avidity.
Is specificity between antigen and antibody relative or absolute?
Relative - there are degrees of specificity.
What is cross-reactivity of antibodies?
When one antibody reacts to another antigen if it's similar enough to the one it's intended for.
What are the four main functions of B cells?
1) Recognize soluble foreign antigens that are extracellular

2) Differentiate into plasma cells and make specific antibody

3) Provide major defense against extracellular microorganisms and toxins

4) Function as antigen presenting cell in T helper cell immunity
What CDs are associated with B cells? Which one with the BCR specifically?
CD19, CD79, CD21, CD40. CD79 with the BCR.
What is the function of CD21 and CD19 in B cells?
Amplify the signal - strengthen the signal that's going across from the BCR.
Which CDs amplify the signal that the B cell is sending?
CD19, CD21.
What is the role of CD40 with B cells?
Bind CD40L on T cells, CD40L is necessary for helper T cells to help B cells.
What kind of antigens do B cells recognize?
Soluble - in blood.
What does B cell signaling require?
Crosslinking by the antigen.
CD79 is required for what function?
Transmembrane signal transduction - is non-covalently associated with Ig receptor.
What does B cell signaling result in?
B cell activates, clonal expansion, differentiation to plasma cells.
Plasma cells produce Igs of same ____ of B cells.
Specificity.
Explain how T-dependent responses of B cells differ from T-independent responses of B cells.

1) What does it happen with?
2) Memory?
T-dependent responses happen with most antigens, usually complex proteins Mutiple determinants, has memory and is efficient in responding.

T cell independent are usually in response to non-proteins - polysaccharides, lipopolysaccharides. Repeated determinants. Weak response, no memory - only IgM is produced, nothing else.

This is why bacteria with capsules (polysacchs) are difficult to respond to.
What do B cells use to present antigen to Th cells?
MHCII molecules.
What protects against bacteria, humoral or cell mediated immunity? What protects against viruses?
Bacteria - humoral
Viruses - cell-mediated
What cytokines are produced by Th1 cells? Th2?
Th1 - IL2, IFN gamma, TNFalpha, TNFbeta, IL-3, GM-CSF

Th2 - IL4,5,6,10, TGFbeta, IL-3, GM-CSF
Which helper cells are responsible for helping B cells? What cyotkines do they secrete specifically to help B cells?
Th2 - secrete IL4, 5, and 6 for B cell activation, proliferation, and differentiation.
Describe the picture/slide with B cell activation and T help.
Naive B cell encounters antigen. Helper T cells stimulate the B cell to:

1) clonally expand
2) differentiate into effector cells (antibody secretors), IgG expressing cells (class switch), high-affinity Ig-expressing cells (affinity maturation and memory cells)
Are T cells required for class switching?
Yes.
Are antigens made immediately in response to antigens? What is the first antibody produced? When does it peak? Describe what happens during the second antigenic challenge.

What determines how long the antigen response lasts? Which response lasts longer, the primary response or the secondary response?
No, there is a lag phase where the B cell is being activated, clonally expanded and differentiated.

The first antibody produced is IgM, doesn't peak for 7-10 days. IgG peaks higher a few days later. Can barely detect antibodies after 3 weeks. Then during secondary antigen challenge, lag is much shorter (3-5 days). IgG produced at a much much higher level.

How long the antigen response lasts is determined by the antigen. Some are detected over many years (ie tetanus).

In general, the secondary response lasts longer than the primary response.
What is an anamnestic response?
Secondary response to an antibody. EVERYTHING AFTER THE PRIMARY RESPONSE IS CALLED THE SECONDARY RESPONSE. Even a fourth reaction to an antigen is called a secondary response.
Compare the following into a primary and secondary response to an antibody:

1) Lag phase
2) Antibody titer
3) Ab isotype
4) Affinity
1) Lag phase:

Primary: Longer - 7-10 days
Secondary: Shorter - 2-4 days

2) Antibody titer

Primary - Lower, short lived
Secondary - Higher, long lived

3) Ab isotype

Primary - IgM -> IgG
Secondary - IgG

4) Affinity

Primary - low
Secondary - high

In secondary, antibodies still have the same specificity, but their AAs have changed a bit to give it a higher affinity to the antigen.
Why is the lag time shorter during a secondary response to an antigen?
During the primary response, you only have 3, 4, 5 B cells responding to the antigen. During the anamnestic response, you have 100s of B cells primed and ready to respond to that specific antigen.
Describe what is needed for isotype (class)switching.
Helper T cell cytokines are needed.

IFNgamma needed for switching to IgG subclasses.

IL-4 needed for switching to IgE subclasses.

TGFbeta needed for switching to IgA (mucosal tissues)
Compare B cell vs. plasma cell:

1) Surface Ig
2) Surface MHC II
3) Ig secretion
4) Growth
5) Isotype switch
1) Surface Ig

B cell - high
Plasma cell - low

2) Surface MHC II

B cell - yes
Plasma cell - no

3) Ig secretion

B cell - no
Plasma cell - yes

4) Growth

B cell - yes (divide and grow by clonal expansion)
Plasma cell - no (end stage, does not divide anymore)

5) Isotype switch

B cell - yes
Plasma cell - no (once they start producing one antibody, they must stick to producing that antibody)
Describe the levels of antibodies in a newborn. When do neonates begin production of their own IgG?
Newborn has b cells, but produces VERY little antibody for first 2-3 months of life. Maternal IgG transferred across placenta.

Neonates begin own IgG production at ~3 months.
How many sets of antigen binding sequences are in an antibody? Which is larger, the potential number of distinct antibodies and T cell receptors, or the number of lymphocytes in the body?
Antibodies have potentially unlimited numbers of antigen binding sequences.

The potential number of distinct antibodies and T cell receptors is far larger than the actual number of lymphocytes in the body.
How is antibody diversity generated?
1) Multiple gene segments on different chromosomes
2) Variable recombination (pool of multiple different types of each segment on different chromosomes)
3) Somatic mutation
What antibodies are produced primarily in the anamnestic response? How is it better than the primary response?
IgG is primarily produced. Better because antibodies are produced faster, last longer, reach a higher titer.
Where are the chromosomes for:

1) Heavy chains
2) Lambda chains
3) Kappa light chains
1) Heavy chains - chromosome 14
2) Lambda chains - chromosome 22
3) Kappa chains - chromosome 2
What are the three segments of the heavy chain? How many of each kind are there?
Variable, joining, diversity. Many of each and they combine to make different combinations!
How many different combinations of VDJ, light chain, heavy chain are there due to combinatorial diversity? What is the name of the mechanism that adds diversity at the junction between genes?
More than 5 million. Diversity at junction between genes - junctional diversity.