Lecture 12: HIV & Aids

Question 1

AIDS
-caused by
-capsid
-genome
-envelope

Answer 1

-caused by: HIV-1 and HIV-2
-complex (conical)
-(+) ssRNA
-enveloped

Question 2

HIV structure

Answer 2

Two important surface proteins
-gp120: docking glycoprotein
-gp41: transmembrane glycoprotein

Capsid protein used for diagnosis
-p24

Genome: (+) ssRNA
Enveloped

Question 3

HIV pathogenesis

Answer 3

-Gp120 binds to CD4 expressed on Mϕ, DC… etc Gp120 binds as well to co-receptor CCR5, expressed on Mϕ and activated Tcells

Question 4

HIV
-antigen
-receptor
-co-receptor

Answer 4

Antigen = gp120(docking protein)/gp160/gp41 (transmembrane protein)
Receptor = CD4
Co-receptor: CCR5 and CXCR4

Question 5

HIV Tropism
-do all HIV viruses infect all types of CD4 cells?
-what happens when HIV mutates?

Answer 5

The type of CD4 cell that HIV will infect depends on the type of co-receptor it has. This will determine if the gp120 infects the CD4 cell.

M TROPISM
- use of Mϕand DC’s and use CCR5 as their preferred co-receptor

T TROPISM
-kill and depleats Tcells more efficiently later on during the infection (HIV mutates) CXCR4 as their preferred co-receptor

Question 6

Which HIV causes the majority of HIV infections in the US and globally?

Answer 6

HIV-1

Question 7

How would you diagnose AIDS?

Answer 7

BY EITHER:
-Having CD4 T Cell count are below 200cells/mmm^3
-having an AIDS-defining condition

Question 8

AIDS-defining opportunistic infections
-bacterial (3)

Answer 8

-Salmonella Septicemia
-Mycobacterium avium-intracellulare complex
-Mycobacterium tuberculosis

Question 9

AIDS-defining opportunistic infections
-virals (4)

Answer 9

-Kaposi’s sarcoma (HHV-8)
-CMV (HHV-5)
-Oral hairy leukoplakia (EBV/HHV-4)
-HSV chronic ulcers (HHV-1 & -2)

Question 10

AIDS defining opportunistic infections
-fungal (5)

Answer 10

-PCP
-Histoplasmosis = type of fungal that hides/lives in the WBC
-coccidioidomycosis = CNS & bone
-oropharyngeal candidiasis
-cryptococcal meningitis

Question 11

HIV Diagnosis
- to confirm HIV+ what tests are required?

Answer 11

First test is a presumptive positive
ELISA
-antigen (p24) and
-antibodies to HIV (against gp160)

second test confirms diagnosis
-ELISA to discriminate b/w HIV-1 from HIV-2 antibodies
-RT-PCR (NAAT) … ONLY if ELISA is negative or indeterminate, then confirm with RT-PCR

Question 12

ART (Anti-Retroviral Therapy)
-naive patients
-experienced patients

Answer 12

Naive patients
-2 NRTs + an integrase inhibitor
Experienced patients
3 drugs review of their drug-resistance test results
-can include
NRTIs, NNRTIs, Fusion inhibitor, CCR5 inhibitor, Protease Inhibitor

Question 13

When is ART (anti-viral therapy) recommended?

Answer 13

ANYONE THAT IS HIV+ AT ANY CD4 COUNT