quiz (retroviruses)

Yusri Arif bin Sapaee

5th 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

eplicati

on c

ycle

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)

Retroviruses are non enveloped positive

sense ssRNA viruses

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?

HIV Lentivirinae subfamily

HTLV Oncovirinae subfamily

Human Immunodeficiency Viruses replicate

in?

HIV-2 is the major cause of AIDS worldwide

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)

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?

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?

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

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

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?

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?

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