Week 4&5 Questions Flashcards
What does PAMP stand for:
What are some examples?
Pathogen-associated molecular patterns. (occur in all pathogens; bacteria fungi etc.)
e.g. viral nucleic acids (Viral RNA), flagellin, envelope proteins
What does PRR stand for:
What are some examples:
Pattern Recognition Receptor
- receptors on cells that detect PAMPS
e.g. Toll-Like Receptors, RIG-I-Like Receptors (RNA receptors), retinoic acid receptors, C-lectin receptors, Nod-receptors
What does TLR stand for?
What are the main TLRs that detect viruses and where are they located in the cell?
Toll like receptors
Toll receptor 2 & 4 are located in cell membrane)
- detect things outside the virus
Endosome ( T3 & &)
- detect single stranded RNA and un-methylated DNA (genome is highly methylated, so it detects the abnormal)
**Cause inflammatory/immune response
Once a virus is detected by a TLR molecules bind to the TLR and then a signalling pathway is activated in the cell that results in being activated. Once activated these translocate to the and ( what do they ultimately do?)
(adaptive molecules bind)
….adapter molecules are activated
….nucleus and triggers the transcription of genes (transcription factors)
Name 2 RLR:
Where are they located in the cell?
What do they ultimately do in the cell? What does the cell produce?
RIG-I-like receptors
1. RIG-I
2. MDA-5
Location: Cytoplasm, cytozole
** Cause Inteferon to produce type I interferons
What do cytokines and chemokines do?
What do type I interferons do?
Cytokines (inflammatory): enhances and triggers immedite immune response
Chemokines: Directs movement of immune cells to site of insult i.e. macrophages and neutrophils (proteins, usually start with CCL) -causes chemotaxis
Type 1 inteferon pathway
Interferon binds to IFNAR (interferon alpha/beta receptor) –> Activation of JAKs (Janus Kinases) (JAK1 and TYK2) –> Phosphorylation of STAT1 & STAT2 (Signal Transducers and Activators of Transcription) –> Translocation to the Nucleus –> Transcription of ISG
What are ISGs and what do they do?
Interferon-Stimulated Genes
- Clear viral infections
- Induce more anti-viral proteins
- Impedes viral pathogenesis
Describe what this is an image of:
The effect of IFITM (Interferon-Induced Transmembrane) proteins effect on fusion in HIV-1.
- the proteins interfere with fusion and interferon response.
- Effectively reducing viral entry and limiting the virus’s ability to infect new cells.
What types of cells do chemokines attract?
- Neutrophils and macrophages
- T & B cells
Name 4 ways (there are 6) in which neutrophils kill viruses:
Phagocytosis
Extracellular traps
Degranulation
Reactive Oxygen Secretion (ROS) release
Name three cell types that present antigens:
What cells do they present antigens to?
Macrophages
Dendritic Cells
B Cells
Antigen to : T Cells
How do the functions of MHC class I and II molecules differ?
MHC class 1 - endogenous molecules, cells infected by viruses, present to CD8 cells (cytoxic). 1 Alpha sheet
- fight viruses and tumours
MHC class 2 - exogenous, pathogenic debris, present to CD4 cells (T-cells then help activate B-cells). 2 Alpha sheets
- coordinate response for external pathogens
Types of T cells and their functions
(T1- 6)
What are the two main functions of B cells?
What happens after a T helper cell binds to a B cell?
Name and describe 3 functions of antibodies:
