Case 9 Flashcards
What molecules recognise a virus in the immediate innate immune response?
Defensins, Lactoferrin, Lysozyme
Preformed soluble effector molecules
What cells recognise a virus in the immediate innate immune response?
Macrophages, Mast cells, Conventional Dendritic Cells
Some memory T cells and NK cells
How does Influenza A target the mucus barrier to infection?
Cytolytic. Causes acute cell death of ciliated respiratory epithelial cells and removal of mucous secreting cells.
Blocks muco-ciliary escalator
Sentinel Cells
First line of defence.
Macrophages, Dendritic cells and a few NK cells.
PRRs recognises
PAMPs
Which Toll-like Receptors are found within endosomes?
TLR 3, 7, 8, 9
TLR3 detects…
dsRNA
TLR7 detects…
single stranded viral RNA
TLR8 detects…
single stranded viral RNA
TLR9 detects…
Unmethylated CpG-rich DNA
intracellular viral infection
Which Toll-like receptors detect viral glycoproteins?
TLR 1, 2, 4, 6
Which TLRs are found on the plasma membrane?
TLR1, 2, 4, 6
Genetic defect in TLR3 signalling pathway is associated with…
Recurrence of Herpes Simplex Encephalitis
How does TLR3 detect HSV-1 (a DNA virus)?
HSV-1 produces a dsRNA intermediate during transcription.
TLR3 detects ds RNA.
Epstein-Barr Virus infects what type of human cells?
B cells
Pyrogens released by macrophages on detection of a virus
IL-6,
TNF-alpha
IL-1 Beta
How do pyrogenic cytokines increase body temperature?
Act on hypothalamus to produce PGE2 (innervation of SNS, non-shivering thermogenesis and vasoconstriction)
Act on muscle to increase fat and protein utilisation,
TLR activation leads to….
Transcription of type 1 interferons (alpha and beta)
RIG-1
Interferon Stimulated Gene
Rig-like receptor involved in triggering interferon expression
MD-5
Interferon Stimulated Gene
Rig-like receptor involved in triggering interferon expression
IFITM3
Interferon Stimulated Gene
Prevents entry of enveloped viruses into cytoplasm by trapping them at plasma membrane.
Where are RLRs located?
cytosol
Interferon Response Factors
Activated by PRRs on detection of PAMPs
Enter nucleus and initiate transcription of type 1 interferons
Effect of Ebola on IFNs
Shuts off supply of interferons, preventing the antiviral state.
What do cytosolic RLRs detect?
Abnormal RNA
A majority of Interferon production in conducted by…
Plasmacytoid Dendritic Cells (pDCs)
Contain extensive rough endoplasmic reticulum.
Plasmacytoid Dentritic Cells are located…
Blood and lymphoid tissue
Plasmacytoid cells express TLRs…
7 and 9
Conventional Dendritic Cells - role…
Activation of naive T cells
Conventional dendritic cells are located (in the absence of infection)…
In peripheral tissues
Why are MMR vaccines not given singly and a week apart?
Interferon response to first vaccine would suppress replication of the second vaccine - diminished immune response.
Would need to be given 30 days apart (child is vulnerable to infection at this time)
NK cells release…
Perforins
Granzymes
IFN-g
Effect on macrophages of IFN-g release from NK cells
Makes macrophages more efficient at phagocytosis
Function of conventional dendritic cells
Transports antigen from site of infection to secondary lymphoid tissues
Cells which express MHC I
Found on surface of all nucleated cells.
MHC I display non-self proteins to…
Cytotoxic T lymphocytes
MHC II display non-self proteins to…
T Helper Cells
CD4
Glycoprotein expressed by T Helper Cells
Involved in detection of MHC II
CD8
Glycoprotein expressed by cytotoxic T cells.
Involved in detection of MHC I
Vaccination into deltoid will reach which secondary lymphoid tissue?
Axillary node
Vaccination into quadriceps will reach which secondary lymphoid tissue?
Inguinal node
Route of administration of influenza vaccine in children
Oral/Nasal
Route of administration of Rotavirus vaccination
Oral/Nasal
cDCs in Peyer’s Patches and Mesenteric Lymph Nodes of Intestines detect pathogen.
Immunoglobulin produced in adaptive immune response is?
IgA
cDCs in Axillary/Inguinal Lymph Nodes of Intestines detect pathogen.
Immunoglobulin produced in adaptive immune response is?
IgG
CCR7
Directs cDC to nearest draining lymph node
Lymph from upper body eventually reaches…
Right lymphatic duct
Lymph from lower body eventually reaches…
Thoracic duct
Intracellular antigens processed into peptides by
Proteasome
Extracellular antigens processed into peptides by…
Endosome used to bring antigen into cell
Why are live-attenuated vaccines the best way to achieve a CTL response?
Only live viruses can replicate intracellularly and be presented by MHC class I
CD4 and CD8 are examples of…
Co-receptors
Function of US6 protein in Human Cytomegalovirus
|nhibits peptide loading of MHC class I. Allows virus to evade recognition mechanisms.
2 Signals for full activation of CTLs by cDCs
- Binding of TCR with MHC:Peptide complex
2. Binding of C7 (upregulated by step 1) with C28 on surface of CTL
Swelling of lymph nodes occurs due to proliferation of which cells?
CD8 T cells/ Cytotoxic T Cells
Function of IL-2
Promotes proliferation and differentiation of T cells (into memory and effector cells)
On detecting virally infected target cells, CTLs release…
Perforins and Granzymes
TH1 cells
Migrate to infected tissues from lymph node to help macrophages
Function of Follicular Helper T cells
Stimulate somatic hypermutation of variable region of immunoglobulins on the surface of B cells.
Antibody on surface of B cells (prior to somatic hypermutation)
IgM
Activated Induced Cytidine Deaminase
Catalyses somatic hypermutation
Hyper IgM Syndrome
Mutation in gene which codes for AID.
B cells can only express IgM on their surface.
Linked Recognition
B cells and T cells must recognise epitopes of the same molecular complex in order to interact.
i.e. Both cells must recognise the antigen to interact.
Conjugate vaccines used for…
Encapsulated bacteria (covered in polysaccharide coat)
Conjugate vaccines consist of…
Protein and polysaccharide
What type of RNA is mRNA?
Positive, single stranded
Function of envelope of a virus
Syncytia formation - allows virus to utilise membranes of host cells.
Non-enveloped viruses are found…
In GI tract (since enveloped viruses cannot survive here)
DNA viruses mutate less frequently than RNA viruses because…
DNA polymerases have a proofreading function (RNA polymerases do not)
Treatment for Genotype 1 Hep C Infection
Sofosbuvir (nucleotide analogue)
Ledipasvir (inhibits viral infection)
Ribavirin (guanosine analogue, blocks RNA synthesis)
Interferons are not used for treatment of infection since…
They cause suicidal thoughts in patients
Pandemic
An epidemic that becomes very widespread, affecting a whole region/continent (may be worldwide).
High mortality.
Forms of Hepatitis spread by contaminated food and water..
A and E
HPV serotype causing cervical carcinoma
16 and 18
HPV vaccine protects against what percentage of cervical carcinomas?
70%
Inactivated polio vaccine protects against…
PV1, PV2 and PV3
Herpangina and Hand-Foot and Mouth Disease are caused by…
Cocksackie A Virus
Clinical Presentation of Cocksackie A virus
Sores in and around the mouth
Form of Hepatitis causing Hepatocarcinomas
Hep C
Clinical Presentation of Dengue Virus
Haemorrhagic Fever: Flushing of face and chest, Oedema, Bleeding, Samll red and purple spots (Petechiae)
Vaccination needed to go on a trip down the Amazon river
Yellow Fever
Major complications of pertussis infection
Weight loss (vomiting) Cerebral Hypoxia (Dyspnoea from cough) Bronchopneumonia
Pertussis infection lasts…
2-3 months
Effect of cytotoxin produced by B.Pertussis
Stops cilia from beating.
Unable to clear mucus from lungs.
Whole Cell Pertussis Vaccine
Reactogenic (seizures, high fever and brain damage)
Longer lived immunity
Acellular Pertussis
Non Reactogenic
Short lived immunity
Immunity resulting from whole Cell Pertussis vaccine is mediated by…
TH17 and TH1
Immunity resulting from Acellular Pertussis vaccine is mediated by…
TH2
Definition of an adjuvant
Substance which enhances immune response to antigens by bringing antigen into contact with immune system
Examples of adjuvants
Aluminium phosphate
Aluminium hydroxide
Molecule responsible for reactogenesis in Whole Cell Pertusis
Endotoxin
How does TH17 elicit immunity to B.Pertussis?
Releases IL-17 which recruits more neutrophils from bone marrow.
Neutrophils mop up extracellular bacteria.
Rubalavirus
Virus causing mumps
Spread of Mumps
Direct contact or droplet
Early symptoms of mumps
Fever Malaise Headache Anorexia Photophobia Earache
Late symptoms of mumps
Swelling of salivary/parotid glands (‘Hamster face’)
Hearing loss
Orchitis
Oophorytis (7%)
Complications of mumps
Encephalitis
Meningitis
Parotitis (Parotid glands)
Permanent Deafness
Diagnosis of mumps
Saliva (Mumps-specific IgM)
Urine
Observations
High serum amylase levels
Treatment of mumps
Treatment of symptoms e.g. Pyrexia using paracetamol
Genes coding for MHC are located on..
Chromosome 6