1. Immunology - Ian Todd Flashcards
- Lymphocytes are made from stem cells found where?
- Where are the 2 places where lymphocytes can mature? And what are the 2 categories of lymphocytes known as?
- Where do the mature lymphocytes go?
- The mature lymphocytes can also go to secondary lymphoid tissues. Name 5 of these…
- Bone marrow
- Bone marrow = B lymphocytes
Thymus = T lymphocytes - Into the circulation
- Tonsils and adenoids, lymph nodes, spleen, peyers patches and bronchus associated lymphoid tissue
Name 5 infectious agents…
Viruses, bacteria, fungi, Protozoa and worms
- What are the 2 types of T lymphocytes?
- When monocytes move out into the blood, what is their new name?
- Name the 4 PMN/ granulocyte cells…
- Name the 5 mononuclear cells…
- CD8+ Tc lymphocytes
CD4+ Th lymphocytes - Macrophages
- Neutrophils, eosinophils, basophils and mast cells
- Monocytes (macrophages), dendritic cells, NK cells, T lymphocytes and B lymphocytes
What are the 2 types of secreted mediators of immunity?
Anti microbial and regulatory/inflammatory
- Which 7 leukocytes are involved in the innate response?
- Which 2 leukocytes are involved in the adaptive response?
- Immunological memory is associated with which response?
- Neutrophils, eosinophils, basophils, mast cells, monocytes (macrophages), dendritic cells and NK cells
- T lymphocytes and B lymphocytes
- Adaptive immunity
Innate immunity
- Activation speed?
- Same/different on repeated exposure to the same microbe? If different then how?
- Efficiency high/moderate/low?
- Recognition of what on the pathogen?
- Recognition by what on the leukocytes?
- Fast
- Same
- Moderate
- PAMP- pathogen associated molecular patterns
- PRR- pathogen recognition receptors
Adaptive (acquired) immunity
- Activation speed?
- Same/different on repeated exposure to the same microbe? If different then how?
- Efficiency high/moderate/low?
- Response is general/broad or specific/tailored?
- Recognition of what on the microbe?
- Recognition by what on the lymphocytes?
- More slowly
- Different - it improves
- High
- Specific tailored
- Antigens
- Antigen-specific receptors
Stages of a primary immune response
- What are the 4 stages called?
- What 2 cells does stage 2 involve?
- In stage 3, what is released? What 2 cells does this attract?
- In stage 4 what is the antigen carried by? Where is it carried to? What 2 cells does this activate? What else is produced? What happens next?
- Epithelial barrier, immediate local response (innate), early induced response (innate/inflammatory) and later adaptive response
- Complement proteins and macrophages
- Inflammatory mediators
Leucocytes and serum proteins (more complement) - Dendritic cells
Lymphoid tissue
T and B lymphocytes
Antibody production
Recirculation to site of infection
Following a primary infection, what can happen on second exposure to the same infection?
Memory T and B cells give a faster and bigger response
- What are the 3 different broad categories of infections?
2. Name the cells involved in each category…
- Extra cellular infection, intra cellular vesicular infection and intra cellular cytosolic infection
- Extra cellular: complement proteins, phagocytes and antibodies
Intra cellular vesicular: Helper T cells
Intra cellular cytosolic: interferon proteins, NK cells and Cytotoxic T cells
What are the 5 types of immunopathology?
Immunodeficiency, allergy, autoimmunity, transplant rejection and lymphoprofilerative diseases
Give an example of 2 pattern recognition molecules that express receptors that can recognise PAMP’s…
Macrophages and Toll-like receptors
When B cells interact with antigens and are activated, they produce a secreted soluble form of their antigen recognition receptors.
- What are these also known as? What is their other name?
- Where are they released?
- Antibodies/immunoglobulin
2. Surrounding environment
What are antibodies?
Secreted soluble form of antigen recognition receptors on B cells
Antigen:antibody interaction
- What can an antigen be? Give an example.
- What shape is a normal antibody?
- Is each antibody specific for/general to each antigen?
- What is at the end of each arm on an antibody? Are they different/identical in terms of which antigen they can bind to?
- What is the precise region on the antigen called where the antigen binds to the arm? What is this also known as?
- Any constituent of the microbe e.g. Surface protein
- Y-shaped
- Specific for
- Antigen combining sites
Identical - Antigenic determinant
Epitope
- What are the 3 types of interactions between epitope on the antigen and combining site on the antibody?
- What type of interactions are these? Do these only work on very short/long distances?
- What kind of affinity do each 3 have?
- Specific interaction, cross reaction and no specificity
- Non-covalent
Very short distances - Specific interaction - high affinity
Cross reaction - moderate affinity
No specificity - negligible affinity
- Are the surface receptors on B lymphocytes inside the cell or membrane bound?
- What is another name for these? (as only the secreted forms are known as antibodies)
- The surface immunoglobulins on a particular B cell will have different/identical antigen combining sites?
- After the antigen combines with the surface B cell, what happens to the B cell?
- The B cell will then differentiate into what type of cell? At this point will it express surface immunoglobulins?
- What will the B cell (now activated and differentiated) spend its energy on now?
- Membrane bound
- Surface immunoglobulins
- Identical
- It becomes activated
- Plasma cell
Will not express surface immunoglobulins - Expressing a secreted form of the surface immunoglobulins which are now called antibodies
- What is the first thing that happens when a B cell binds to an antigen?
- What advantage does this have?
- What happens to the B cells that are activated but don’t differentiate into plasma cells? When would these cells become reactivated?
- B cell proliferates and makes copies of itself
- Expands the pool/clone of lymphocytes specific for that antigen
- They become memory cells with epitope a specific for that antigen
Reactivated on repeat exposure to same antigen
- A secondary response to an antigen is efficient in which 2 ways?
- Is this a key feature of innate or adaptive immunity?
- Bigger response
Faster response - Adaptive immunity
- What form of a toxin is used in a vaccination?
- What cells does a vaccination aim to produce?
- The response is which 2 things?
- Toxoid
- Memory B cells
- Bigger and faster
Immunoglobulins structure (antibody structure)
- What shape is it?
- What is at the end of each arm?
- How many polypeptide chains is it made out of? What two groups can they be divided into?
- Are the chains within each group identical/different to one another in the group?
- Each chain is made of building blocks called what?
- Y-shaped
- Antigen combining site
- 4 chains
2 light chains and 2 heavy chains - Identical
- Immunoglobulins domains
Immunoglobulin structure
- What is the terminal domain on the heavy chain called?
- What is the terminal domain on the light chain called?
- What does the first letter stand for?
- How is this word related to its structure?
- Molecularly, what is different in this region?
- Where is there the most difference in this region?
- VH domain (v heavy domain)
- VL domain (v light domain)
- Variable
- The Vh and Vl domains make up the antigen combining site. They are variable so different antibodies can recognise different epitope.
- Amino acid sequence
- Hyper variable region
Immunoglobulin structure
- About from the variable domains, what other domains are there?
- What are these regions not involved in?
- What kind of bonds are there between the heavy and the light chains?
- What is the flexible part of the heavy chain called? What does this allow?
- C domains = constant domain
- Antigen recognition
- Disulphide covalent bonds
- Hinge region
This allows the arms to move
Immunoglobulin structure
- What is the part above the hinge region also known as? What does this stand for?
- How many of these are there?
- What is the part below the hinge region (the stem) also known as? What does this stand for?
1. Fab region Fragment antigen binding 2. 2 Fab regions 3. Fc region Fragment crystallisable
- How many classes/isotopes of immunoglobulins are there?
- Name the classes…
- What distinguishes one class from another?
- Name the Greek equivalents of the chains mentioned on your answer to question 3.
- What type of surface immunoglobulin are all B cells initially programmed to make?
- 9
- IgM, IgG (1,2,3,4), IgA (1,2), IgE and IgD
- The precise structure of the constant domains in the heavy chain
- Miu, gamma, alpha, epsilon and delta
- IgM
- When a B cell binds to an antigen, is activated and proliferates, what do some of the IgM antibodies undergo?
- Does this happen before or after secretion?
- What difference does this change make?
- What remains the same?
- Class switching
- Before secretion
- The antibody will use a different gene to encode the heavy chains in the constant domains
- The antigenic specificity
- What is the hinge region like on IgG 1,2 and 4?
- What is the neck like on IgG3?
- What additional thing does IgE have?
- IgA can form what shape? How many antigen combining sites does it therefore have? What holds it together?
- What shape is IgM secreted as? How many antigen combining sites does it therefore have? What holds it together?
- Short
- Long and rigid
- Constant domain
- Dimer
4 antigen combining sites
Polypeptide called the J chain (joining chain) - Pentamer
10 antigen combining sites
J chain
Name the tissue distribution of the following antibody isotypes:
- IgM? (x1)
- IgG? (x3)
- IgA? (x3)
- IgE? (x1) bound to which type of cell?
- IgD? (x1)
- Blood
- Blood, tissues and placental transfer
- Blood/tissues, mucosal secretions and milk
- Tissues (bound to mast cells)
- Mucosa of upper aerodigestive tract
Which antibody isotypes interact with the following defence components:
- Complement activation (x2)
- Phagocyte binding (x2)
- Mast cell binding (x1)
- NK cell binding (x1)
- IgM and IgG
- IgG and IgA
- IgE
- IgG
- Does Fab or Fc region bind to the microbe?
2. Does the Fab or Fc region stick out? What does this allow it to do?
- Fab region
- Fc region
It can interact with other immune defence components
- What can phagocytes do to microbes in order to get rid of them?
- What 2 cell types are phagocytes?
- Engulf microbes by taking them into their cytoplasms and then digesting them.
- Macrophages and neutrophils
- What is complement a collection of?
- Which 2 places is it found?
- What does it complement the effects of?
- Various complement proteins can act as what 3 things?
- What 2 things activate complement proteins?
- Complement proteins in what kind of a pattern (with amplification)?
- What is the central event of complement activation?
- Proteins
- Circulation and tissue fluids
- Antibodies
- Activation enzymes, immune defence molecules and control proteins
- Infection and immune activation
- Cascade
- Conversion of C3 into C3a and C3b
- How many C3 convertases are there?
- How many pathways can create C3 convertase? What are the names of the pathways?
- Describe the first step of each pathway…
- 2
- 3 pathways
MB-lectin pathway, classical pathway and alternative pathway - MB-lectin pathway: MBL binds to microbial mannose
Classical pathway: (antigen+IgM or IgG) interact with complement proteins [C1q]
Alternative pathway: C3b binds to microbial surface plus Bb plus P
Complement
Classical pathway
1. Which complement protein interacts with an antibody bound to an antigen?
2. Which 2 antibodies can this be?
3. Which 2 complement proteins does this then activate?
4. What 2 complements does this split?
5. Fragments of this combine to form what? What is this also known as?
- C1q
- IgM or IgG
- C1rs or C1s
- C2 and C4
- C4b2a
C3 convertase
Complement
MB-lectin pathway
1. What does MBL stand for?
2. What does it bind to?
3. What does this trigger the activation of?
4. What does this then breakdown to? This will reassemble to form what?
5. What is this known as?
- Mannon binding lectin
- Microbial mannose
- MASP-1 and MASP-2
- C4 and C2
C4b2a - C3 convertase