12 - Acquired Immunodeficiency Syndrome

Question 1

Coreceptors used by HIV in early and late infection and their tropism?

Answer 1

CCR5 ▶️ early infection, macrophage tropic

CXCR4 ▶️ late infection, T-cell tropic

Question 2

What does the Nef gene do as virulence factor of HIV?

Answer 2

⬇️ class I MHC expression ▶️ makes infected cells less susceptible to be killed by CTL

Question 3

How does the HIV evade the antibody-mediated effector mechanisms?

Answer 3

Antigenic drift of gp120 ▶️ evade humoral effector mechanism

Glycosilation of gp120 ▶️ hide potentially protective epitope from immune recognition

Question 4

What cells serve as HIV reservoirs?

Answer 4

Macrophages

Question 5

What determines speed progression to AIDS?

Answer 5

Mutation in CCR5:

• homozygous: not infection
• heterozygous: low progression

Question 6

Principal that mainly suffer the HIV infection?

Answer 6

TH cells

Destroy CMI and HMI response

Question 7

Proportion of babies born infected from HIV (+) mother with and without treatment

Answer 7

Treated HIV mothers ▶️

Question 8

What is the isotype of antibody produced against envelope antigens in full-blown AIDS? Why?

Answer 8

IgM
In full-blown AIDS, the patient has lost the TH2 cells necessary for isotype switching, so B cells are “stuck” making IgM