Module 2: Section 2A

Question 1

2 ways HIV interacts with host cell

Answer 1

1. Nonspecifically with negatively charged proteins on the host cell
2. Specially with host receptor proteins like CD4

Question 2

Step 1 of HIV interaction with host cell

Answer 2

Spikes are formed by the Env protein consisting of gp41 and gp120

Question 3

Step 2 of HIV interaction with host cell

Answer 3

Gp120 subunit binds to host protein called CD4

Question 4

What is CD4?

Answer 4

Glycoprotein found on the surface of immune cells

Question 5

Step 3 of HIV interaction with host cell

Answer 5

• When Env changes shape, gp120 binds to a host coreceptor
• part of gp41 (the fusion peptide) pushes into the host cell membrane

Question 6

Step 4 of HIV interaction with host cell

Answer 6

• The complexes rearrange to bring the viral envelope and host membrane together
• Allowing fusion of these membranes and delivery of the viral genome into the cell

Question 7

Antiviral drug #1 for HIV

Answer 7

• Soluble form of CD4 molecule
• Bound to gp120 before the virus came into contact with the host cell
• Didn’t work with all strains of HIV

Question 7

Antiviral drug #2 for HIV

Answer 7

• Drug: Maraviroc
• Binds to the host’s coreceptor, blocking HIV’s gp120 from attaching

Question 8

Antiviral drug #3 for HIV

Answer 8

• Drug: Enfuvirtide
• Mimics the gp41 fusion peptide, blocking it from entering the host cell membrane
• Must be injected and is expensive

Question 9

Adenoviruses

Answer 9

• Common cause of acute respiratory viruses
• Have large double stranded DNA genomes and do not possess an envelope
• Have spikes

Question 10

Important note about CAR

Answer 10

Because CAR is found on many cell types (respiratory tract, eye, GI tract), adenovirus can cause illnesses like cold, conjunctivitis, and gastritis

Question 11

Adenovirus binding - step 1

Answer 11

Tip of the adenovirus spike binds to the glycoprotein CAR in the host membrane

Question 12

Adenovirus binding - step 2

Answer 12

• Virus binds tightly to host integrins at the spike base, then enters by endocytosis
• Hard to target adenovirus with treatments

Question 13

How many types of influenza viruses?

Answer 13

• 3 types, A,B and C
• A and B are the only strains that have seasonal out breaks in humans and we only vaccinate against A and B

Question 14

Influenza B

Answer 14

Milder and has evolved 2 linages

Question 15

Influenza A

Answer 15

classified by 2 surface proteins: Hemagglutinin (HA) and Neuraminidase (NA)