Virology 3 Flashcards
(10 cards)
Virus infection can be prevented or slowed by?
Antibody that neutralises the virus
Cells that kill virus infected cells before progeny virus is released
Antibody that bindsto infected cell surfaces and fixes complement
Antiviral cytokines such as interferon
Soluble inhibitors such as mannose-binding lectin
Phagocytosis by macrophages
Antiviral drugs
Describe prevention of virus by vaccination?
Establish a pool of memory of T and B cells.
Describe the 2 memory responses induced by vaccination that are relevant to viral infection?
1) Memory CD8 T cells > killing of irus infected cells by CTL
2) Memory B cells> neutralisation of virus by antibody
- neutralisiing Ab generally directed against surface proteins
- Prevent attachment or subsequent stages of infection
- antibody may also promote opsonisation or Ab+C lysis
3) Memory CD4+ T cells > help B cells make antibody, help CD8+ T cells develop into memory cells
Why must a new vaccine be produced against influenza every year?
Accumulation of mutations in the sites to which antibodies bind -antigenic drift
Antigenic drift occurs due to?
SSpontaneous and point random mutations in theviral RNA genome
Selection of viruses that have mutations that reuslt in aminoacid subs in the antigenic sites of the HA
Dscribe the treatment of virus with antiviral drugs
Works by inhibiting particular stages of replication
Nucleoside has no what
No phosphate group
Acyclovir is what
A nucleoside analogue
What type of analogue is acyclovir
Guanosine
Phosphate groups can be added to acyclovir so that the analogue can be incorporated into DNA. But the 3’ hydroxyl group reuired to extend the DNA polymer is what?
Absent
