HIV/AIDs

Question 1

What is a retrovirus?

Answer 1

RNA virus that inserts copy of genome into DNA of host cell that’s its invading.

Question 2

What does reverse transcriptase do?

Answer 2

Copying of RNA template into double stranded DNA copy.

Question 3

What is integration?

Answer 3

The covalent insertion of a viral cDNA into genome of infected cell. It forms a provirus.

Question 4

What is found on the outer envelope of HIV?

Answer 4

Lipid bilayer with envelope spikes.

Question 5

What is found in the core for HIV?

Answer 5

Two genomic RNA strands, tRNA Lys 3, 50 copies of each viral enzyme.

Question 6

Where does HIV originate from?

Answer 6

Simian immunodeficiency virus - species of retrovirus found in chimpanzees.

Question 7

What is HIV’s affect on CD4 count?

Answer 7

Results in CD4 depletion.

Question 8

What is major target tissue for HIV?

Answer 8

Gut-Associated Lymphoid Tissue (GALT).

Question 9

Give 2 mechanisms of CD4 T cell depletion.

Answer 9

Cytopathicity - direct killing by the virus. Cytotoxic T cell - killing of infected cell. Immune hyperactivation - lots of CD4 T cells activated, makes them more susceptible to infection.

Question 10

Give 2 diagnostic tests for HIV.

Answer 10

Enzyme-linked immunoassay (ELISA) - presence of anti-p24 antibodies in serum. Viral level test (>100,000 RNA copies/ml). Leukopenia (reduced CD4 count).

Question 11

Name 3 opportunistic infections.

Answer 11

Kaposi’s Sarcoma - human herpes virus 8. Fungal pneumonia. Toxoplasmosis. Reactivation of oral/genital/anal herpes simplex virus. Cytomegalovirus-induced retinitis. Tuberculosis.

Question 12

What is Kaposi’s sarcoma (KS)?

Answer 12

Kaposi’s sarcoma (KS) is a type of cancer that can form masses in the skin, lymph nodes, or other organs.

Question 13

What is toxoplasmosis?

Answer 13

Parasitic disease. People may have a few weeks or months of mild, flu-like illness such as muscle aches and tender lymph nodes. In a small number of people, eye problems may develop.

Question 14

How does HIV evade CD4 T cells?

Answer 14

Through mutations. Using T cells as substrates.

Question 15

What does HAART stand for?

Answer 15

Highly Active Anti-Retroviral Therapy (HAART). It is a combination therapy - difficult for HIV to mutate to avoid combinations of drugs.

Question 16

What are the 4 types of medication?

Answer 16

Entry inhibitor e.g. CCR5 inhibitor, T20 inhibitor. Reverse transcriptase inhibitor e.g. Nucleoside-analogue reverse transcriptase inhibitors (NRTI) and Non-Nucleoside-analogue reverse transcriptase inhibitors (NNRTI). Integrase inhibitor e.g. Raltegavir. Protease inhibitor e.g. Ritonavir, Darunavir.

Question 17

How do Enfurvitide and Maraviroc work?

Answer 17

They are entry-inhibitors.

Question 18

How does Raltegavir work?

Answer 18

Integrase inhibitor - prevents viral DNA being integrated into host cell DNA.

Question 19

How does Ritonavir and Darunavir work?

Answer 19

Protease inhibitor.

Question 20

Give 2 ways how HIV can be prevented.

Answer 20

Effective condom use. Male circumcision e.g. reduces heterosexual transmission. Pre-exposure prophylaxis (PrEP) - taking anti-retroviral therapy before getting HIV. Topical microbicides - gels containing anti-retroviral drugs.