L09 Flashcards
Different effector mechanisms depend on
Type of pathogen, localisation and stage of infection
What type of MHC class would be required for an extracellular infection?
MHC II
What type of MHC class would be required for an intracellular infection?
MHC I
What are the innate defenses against viruses
Interferons and NK cells
What type of interferons are present in responding to a virus
IFN - alpha and beta
How do IFN-alpha and IFN-beta help respond to the virus?
Prevents nucleic acid production/replication
What do chemokines recruit?
Lymphocytes
How does IFN-alpha and IFN-beta prevent viral nucleic acid production/replication
Induce resistance to viral replication in all cells by inducing Mx proteins, 2’-5’ linked adenosine oligomers, and the kinase PKR.
Increase MHC class I expression and AG presentation in all cells
Activate dendritic cells and MQ
Activate NK cells to kill virus-infected cells
Induce chemokines to recruit lymphocytes
What type of interferons are there?
1
How does IFN result in viral mRNA degradation?
2,5’ - oligoadenylate synthetase = adenine trinucleotide synthesis = activates endonuclease = degrades viral mRNA
How does IFN inhibit protein synthesis
Protein kinase = phosphorlyation and inactivation of eIF-2 = inhibits protein synthesis
What cells make IFN alpha and beta?
Infected cell
When is IFN alpha and beta synthesised?
Early response to infection
What cells secrete type II IFN (IFN - gamma)
NK and activated T cells
What does IFN gamma do?
Inhibits TH2 response (Ab), promotes TH1 (NK), recruits Mq
What are the therapeutic use of interferons?
rIFN-alpha - hepatitis B and C, some cancers.
What are the disadvantages of using IFN for therapeutic treatments?
Side effects can be severe
Why can there be severe side effects for therapeutic treatments using IFN?
Cytokine storm -> excessive immune response can damage healthy cells and organs
Are NK cells large granular lymphocytes?
Yes