retrovirus

Question 1

what is a retrovirus

Answer 1

enveloped, positive strand RNA. Contains reverse transcriptase which produce provirus that integrates into host genome.

Question 2

what are the 3 major proteins encoded in retrovirus genome

Answer 2

Gag, Pol, Env

Question 3

What is the target cell binding of HIV

Answer 3

CD4 receptor on T cell lymphocyte

Question 4

How does dendritic cell inititate HIV infection

Answer 4

transport HIV from mucosal surface to lymphoid tissues

Question 5

what are the 5 diff ways antivirals can act against HIV

Answer 5

• Fusion inhibitor
  ○ Drug binds to gp41 and blocks formation of post fusion structure
  
  • Reverse transcriptase inhibitor
  • Entry inhibitor
    ○ Drug binds to CD4 surface proteins to prevent HIV from binding to cell
  • Integrase Strand transfer inhibitor
    ○ Prevent HIV provirus from integration to host
  • Protease inhibitor
    Blocks action of protease enzyme required to cleave HIV polypeptides

Question 6

What is the pathogenesis of HIV

Answer 6

causes lytic and latent infection of CD4 T cell and persistent infection of monocyte, macrophage, dendritic cells

disrupts neuron function

leads to acute febrile illness, long clinical latency period as well as a progressive loss of CD4 T cells accompanied by opportunistic infection

Question 7

What does CD4 T cells do

Answer 7

• control of non lymphoid cell growth and B cell
• control of growth of CD4 and CD8 T cell. Controls latent viruses, tumours, HIV progression
• Activates macrophages and neutrophils, help control intracellular bacteria, fungi, virus infection

Question 8

How is HIV transmitted

Answer 8

blood, semen, sexual intercourse, peripartum transmission

Question 9

What can block HIV from entering the cell

Answer 9

• Saliva, Because saliva contains IgA antibodies to HIV proteins, may neutralise infectivity of the virus
• high molecular weight mucins can entrap virus
• salivary leucocytes protease inhibitor, can block cell surface receptor needed for entry of HIV into cell

Question 10

What can kill HIV virus

Answer 10

• inactivated by heat, inactivated 100 fold each hour at 60 deg

-2% glutaraldehyde and hypochlorite

Question 11

some examples of illnesses of AID

Answer 11

herpes simplex chronic ulcer, cytomegalovirus, mycobacterium tuberculosis, HIV encephalopathy… GOT ALOT MORE AH, oral hairy leucoplakia

Question 12

What is karposi sarcoma

Answer 12

tumours arising from endothelial cell of blood vessels… due to HHV 8. Bluish purple, raised irregular lesions

Question 13

How do you diagnose HIV

Answer 13

• test antibodies specific to the virus in serum or other fluid
• HIV RNA PCR
• HIV antibody or HIV antigen-antibody combination test

need to have at least
- CD4 count fewer that 200cell/microliters of blood

• test positive for virus and experience one or more of the CDC provided list of AIDS defining illness

Question 14

How to prevent HIV

Answer 14

safe sex, the antiviral drugs like reverse transcriptase inhibitors, protease inhibitors

Question 15

How does protease inhibitors stop HIV drugs from mounting an infection

Answer 15

protease inhibitors plug into active site of HIV protease, during budding, viruses incorporate this uncut non functioning protein causing virus to be unable to mount infection

Question 16

Why is HIV so hard to treat

Answer 16

mutation occurs alot and has error prone replication and latent and persistent infection of monocytes, macrophages etc