What are the most common cells outside the blood?
Mast cells
What is viral tropism?
How only specific viruses can be taken up by specific tissues
Where and how are self-reactive T cells removed?
By negative selection in the thymic medullary cells
Where is antigen presented to T cells?
On antigen binding grooves
Which ligand does NOD-1 recognise?
y-glutamyl diaminopimelic acid
How do CD4 T cells respond to IL-4?
By differentiating into Th2 cells
Where are nTregs produced?
In the thymus
Which ligand does TLR-1 dimer and TLR2/6 dimer recognise?
Peptidoglycans, lipoproteins, mycobacteria, GP1, zymosan
Which T cells recognise MHC class I?
CD8
Give an example of gram negative cocci.
Gonorrhoea, meningococcal meningitis causing
What do CD4 and Th2 secrete to help B-cells?
IL-4, IL-13
Which cells are involved in the tuberculin response of type IV hypersensitivity?
Th1, IFNy and IL-2 attract macrophages
How do CD4 T cells respond to IL-12?
By differentiating into Th1 cells
Give an example of gram positive rod.
Spore forming e.g. antharax, tetanus
What are acid-fast bacteria? Give an example.
Do not stain, have waxy mycolic acids in cell wall. E.g. mycobacterium tuberculosis.
What does the alternate system of complement recognise?
The pathogen
Give an example of gram positive cocci.
Staphycoccus aureus, streptococci pneumoniae, enterococci, strep. A, B & C
What is suppurative inflammation?
Pus is present
What do CD4 and Treg secrete to inhibit immune response?
TGF-B, IL-10
Which ligand does TLR-5 recognise?
Flagellin
What do the cytokines IL-12 and TNFa mediate?
Fever, macrophage activation, CD4 T-cell differentiation
What happens in type II hypersensitivity?
IgG and IgM activate complement cascade, releasing C3a and C5a, recruiting inflammatory cells and allowing killer cell attack
Which antibody will be dominant when reacting to a pathogen never seen before?
IgM
Which out of gram positive and gram negative bacteria survive drying better?
Gram positive
Which MHC is expressed on all nucleated cells?
Class I
When is a T cell activated?
When CD4 or 8, MHC and TCR bind and CD28 binds to CD86
What do T cell receptors consist of?
alpha beta or gamma delta chains
What happens in type I hypersensitivity?
Mast cell degranulation due to cross linking of IgE activated by histamine, tryptases, prostaglandins, leukotrienes and cytokines
Which cells make interferons?
Virally infected cells
Describe inoculation
Virus directly enters blood
What kind of selection does a thymocyte undergo for MHc affinity?
Positive selection
Which antigens are presented on MHC class II?
Exogenous antigens
What lineage do natural killer cells have?
Lymphoid
How is diversity of antibody specificity achieved?
By random genetic recombination
Is adenovirus RNA or DNA based?
DNA
What genes are heavy chains made of?
V, J and D genes
Which antigens are presented on MHC class I?
Endogenous antigens
Why does antibody specificity vary?
Due to differences in VH and VL sequence
What does absence of recombination activity in receptor formation in the adaptive immune system cause?
SCID (severe combined immune deficiency)
What cells do CD4 and Th17 activate?
Neutrophils
Which cells are involved in the asthma response of type IV hypersensitivity?
Th2, IL-4, IL-8,IL-13 attract eosinophils
Is hepatitis B virus RNA or DNA based?
DNA
Give an example of gram negative rod.
E. coli, salmonella, anaerobes, legionella, haemophilus, shigella, brucella, proteus, pseudomonas
What does a T cell do when it is activated by a virally infected cell?
Causes the cell to die by apoptosis
What is membranous inflammation?
Membrane produced over surface of inflamed tissue
Where does affinity maturation of B cells occur?
In B cell follicles
What does detection of PAMPs cause?
Migration of antigen presenting cells to secondary lymphoid organs
Which out of gram positive and gram negative bacteria has teichoic acid in cell wall?
Gram positive
What are the PRRs in cell membranes?
Toll like
Which out of gram positive and gram negative bacteria produces spores?
Gram positive
What produces the chemokine IL-8?
Macrophages and endothelial cells
Which cytokines do natural killer cells respond to?
TNFa and IL-12
Which ligand does TLR-9 recognise?
Unmethylated CpG DNA
Which out of gram positive and gram negative bacteria has a cell membrane?
Gram negative
Is herpes virus RNA or DNA based?
DNA
Describe the hepatitis B virus
Hepadnavirus ds DNA genome, icosahedral symmetry with envelope
Describe the influenza virus
Orthoxovirus ss- RNA genome helical symmetry with envelope
Is picornavirus RNA or DNA based?
RNA
What genes are light chains made of?
V and J genes
Which cells are destroyed by the HIV virus?
CD4 T cells
What are the type-1 interferons?
IFNa and IFNb
What is the mechanism of fever?
Increased cytokine production, reset set point of hypothalamus. PGE2 produced by hypothalamus.
What do the cytokines IL-1 and IL-6 mediate?
Inflammation and fever
How do CD4 T cells respond to IL-6 and TGF-B?
By differentiating into Th17 cells
Which interferon do natural killer cells produce?
IFNy
Which genes encode MHC?
A, B and C
What does the classical system of complement recognise?
Antigen:Antibody complex
What is complement responsible for?
Creation of membrane attack complex
What are the 6 stages of lytic viral infection?
- Replication
- Assembly of capsids with new nucleic acid
- Release of capsid from cell
- Binding of capsid to host cell
- Penetration of host cell by membrane fusion
- Capsids release DNA/RNA
Describe the Varicella zoster virus
Herpse virus ds DNA genome, icosahedral symmetry with envelope
Which immunoglobulin is found as a dimer?
IgA
Describe the HIV virus
ss+ RNA, icosahedral symmetry with envelope
Which immunoglobulin is used in a parasitic infection?
IgE
Is retrovirus RNA or DNA based?
RNA
What happens in type III hypersensitivity?
IgG activates complement cascade, releasing C3a and C5a, recruiting inflammatory cells and allowing killer cell attack in serum
What happens in toxic shock syndrome?
Toxins are produced by S. aureus or pyrogens called superantigens which allow binding of MHC cells with T cell receptors meaning up to 20% of T cells are activated against host cells causing multi-organ failure
What do CD4 and Th1 secrete to target intracellular pathogens?
IFNy and IL-2
Where are collectins found?
In serum
What does the membrane attack complex form from?
C5b, C6, C7, C8, C9
How do CD4 T cells respond to IL-2 and TGF-B?
By differentiating into Treg cells
When are interferons IFNa and IFNb produced?
In response to virally infected cells
Which ligand does NOD-2 recognise?
Muramyl dipeptide
What does C3b cause?
Production of the membrane attach complex
What does the MB lectin system of complement recognise?
Mannose on pathogen
Which antibody will be dominant when reacting to a pathogen encountered before?
IgG
What kind of pathogen is a Helminth?
A parasite
What are digestive enzymes kept inside in a phagocyte?
Lysosomes
Which genes code for the constant region of antibody?
C genes
Which region of antibody determines its function?
The constant region
Which T cells recognise MHC class II?
CD4
Which ligand does TLR-4 dimer and CD14 recognise?
LPS on gram negative bacteria
What domains does a T cell receptor have?
aC, bC, aV, bV
How do CD4 and Th1 activate CD8?
Via IFN-y and IL-2
Where and when are cell adhesion molecules expressed?
On epithelium in inflammation and always on WBCs
Which cells mediate type I diabetes?
Mainly T cells
Which cells mediate allergy?
CD4 and Th2 cells
What do CD4 and Th17 secrete to target extracellular bacteria and fungi?
IL-17, IL-21
Which out of gram positive and gram negative bacteria has endotoxin in cell wall?
Gram negative
Why do T cells not destroy self cells?
Self reactive cells are inactivated before maturation
Which ligand does TLR-3 recognise?
dsRNA
Which immunoglobulin is effective at activating complement?
IgM
