Quiz (Retrovirus

es)

Yusri Arif bin Sapaee5th Year Medical Student

Kasr El-Ainy School of Medicine, Cairo University

Classification of retroviruses that cause disease in humans

Structure of the human immunodeficiency virus

HIV proviral genome

Binding of HIV to surface of lymphocyte

Attachment and entry of HIV virus

The H

IV r

eplic

ati

on c

ycl

e

Common modes of transmission of HIV

Typical time course of HIV infection

Pathogenesis of HIV

Pattern of opportunistic infections associated with declining CD4+ cell counts

Highly active antiretroviral therapy (HAART)

TRUE or FALSE?TRUE or FALSE?

Retroviruses are non enveloped positive sense ssRNA viruses

TRUE or FALSE?TRUE or FALSE?

Retroviruses contain enzyme reverse transcriptase

Retroviruses rely on the reverse transcriptase (RT) enzyme to

transcribe their genome from RNA into a DNA copy, which can then be integrated as a DNA provirus into the genomic DNA of the host cell.

Important members of Retroviridae family that affect humans are?

Human immunodeficiency virus (HIV) and Human T-cell lymphotropic viruses (HTLV)

HIV Lentivirinae subfamilyHTLV Oncovirinae subfamily

Human Immunodeficiency Viruses replicate in?

CD4+ T helper cells

TRUE or FALSE?TRUE or FALSE?

HIV-2 is the major cause of AIDS worldwide

A.

B.

C.

D.

E.

HIV-2 is characterized by the following EXCEPT:

First described in 1986

Slower in progression

Limited mostly to West Africa and Portugal

Much less severe

Has 2 groups (M & O)

TRUE or FALSE?TRUE or FALSE?

Group M viruses are rare and limited to western part of Africa

HIV-1 and HIV-2 resemble each other strikingly. However, they differ in?

Molecular weight of their proteins and accessory genes

The virus has spherical shape with a diameter of 100nm.

The virus envelope is line with an HIV protein called p17 (matrix protein, MA).

Inside, a conical-shaped capsid (CA) made of protein called p24 (core antigen)

What is the most abundant protein in the virus particle?

p24 (core antigen)

Envelope antigens

Core capsid antigens

RT antigen

Its absence successful tx

Responsible for receptor binding

gp120

p66/51 complex

gp120 (SU) & gp41 (TM)

p17 and p24

p24

HIV antigens

A.

B.

C.

D.

E.

Cells that are not infected by HIV

Monocytes/macrophages

Follicular dendritic cells (FDCs)

CD4+ T helper lymphocytes

Oligodendrocytes, astrocytes, neurones and glial cells

Hepatocytes

Name receptors on the cell surface required for the entry of HIV into the cell

CD4 receptor and co-receptor CCR5 & CXCR5

First

Second

Third

Forth

Fifth

Assembly and budding

Transcription

Reverse transcription

Integration

Translation

Post-fusion events

HIV antibody positive

HIV antibody negative, HIV RNA detectable

HIV antibody negative, HIV RNA viral load >5000 copies/ml

HIV antibody negative, HIV RNA viral load 50-5000 copies/ml

HIV antibody negative, HIV RNA viral load <50 copies/ml

Not infected

Acute HIV infection

Established HIV infection & no acute infection

Repeat HIV RNA test in the same specimen

Indeterminate repeat testing on follow up specimen

Diagnosis of acute HIV infection(acute retroviral syndrome)

How to diagnose HIV infection in newborns?

PCR or viral load

Nucleoside analogues transcriptase inhibitors

Non-nucleoside analogues transcriptase inhibitors

Protease inhibitors

Protease inhibitors

Fusion inhibitors

Enfuvirtide (Fuzeon)

Ritonavir

Lamivudine

Nevirapine

Indinavir

Highly active antiretroviral therapy (HAART)

How to monitor anti-HIV therapy?

Viral load measurement & CD4 count

A.

B.

C.

D.

E.

Best regimen for post-exposure chemoprophylaxis

1 reverse transcriptase inhibitor + 2 protease inhibitor

1 reverse transcriptase inhibitor + 1 protease inhibitor

2 fusion inhibitors + 1 protease inhibitor

1 reverse transcriptase inhibitor + 2 fusion inhibitors

2 reverse transcriptase inhibitors + 1 protease inhibitor