Atypical Immune Responses Flashcards
What is the difference between sterilising and non sterilising immunity?
Sterilising immunity will mostly lead to recovery.
Non-sterilising immunity will lead to chronic infection as the virus fails to clear entirely.
How does myobacterium tuberculosis avoid immune clearance?
-They can be phagocytosed and survive as they become coated with coronin, inhibiting its ability to fuse with lysosome.
If it does fuse it can neutralise this and resist phagosomal acidification by pumping out protons avidly.
How can ability of macrophages to phagocytose be enhanced?
Cytokines interferon gamma is produced by CD4 cells.
What type of virus is HIV?
Envelope virus
Retrovirus
Does HIV lead to sterilising or non sterilising immunity?
Non-sterilising
How does HIV avoid immune clearance?
At start CD8 cells help keep virus in check, eventually HIV produces copies and as it is poor at doing so, mutants arise. Eventually it evades the immune system when the failure of CD4 (the cell it infects) occurs.
What is the life cycle of dengue like?
Mosquito bite – extrinsic incubation – human infection – intrinsic incubation
What are the symptoms of non-complicated dengue?
- high fever and chills
- usually a rash
- lasts 3-7 days
What are the symptoms of severe dengue?
- severe plasma leakage
- severe haemoragge
- severe organ impairment
What is the typical response to dengue?
Good response, IgM and IgG play a big role in clearing it.
How does dengue evade immune response?
Infection by different strain gives worse infection, antibody response leads to immune enhancement.
Enhances other strain by enhancing uptake of virus by macrophages through opsonization.
What was wrong with the degue vaccine?
It worked for people who had previously been infected, however if you were vaccinated but hadnt seen dengue before it could lead to worse results.
