Virsuses:Human Immunodeficiency Syndrome

& Acquired Immunodeficiency

Syndrome

Outlinewe may need to save some topic in lecture

• Origins of HIV based on scientific evidence• HIV viral particle• Mechanism of infection• Transmission• Treatment• AIDS• Prevention• Clinical Detection and Diagnosis

Greater spot nose monkey Red capped mangabey monkey

SIV cpz almost identical to HIV 1

Humans

Pan troglodytes troglodytes

Simian Virus (SIV cpz) almost identical to HIV 1

Sooty mangabey monkey

Simian Virus corresponds to HIV2

HIV: Structure and mechanism of replication

HIV

HIV-1 PARTICLE

The key HIV genes

Mechanism of Infection

VIRAL RNA

PROVIRAL DNA

Infects Th cell

Integrates into host DNA

“activated”LYTIC STAGE storage

LYSOGENIC STAGE

RETROVIRAL REPLICATION

HIV animations

http://search.live.com/video/results.aspx?q=HIV+animation&docid=1601834254601#docid=1601834254601

http://search.live.com/video/results.aspx?q=HIV+animation&docid=1601834254601#docid=1669495456158

http://www.hivinfosource.org/hivis/hivbasics/animations/index.html

T lymphocyte in green and HIV in red

HIV and helper T cells

HIV-1

HOST CELLS: helper T lymphocyte, macrophages

LYTIC STAGE

Transmission of HIV

Transmission of HIV

• Biological fluids

– Blood– Sexual transmission (Semen)– Breast milk– Transplant tissues

Non-transmitting sources of HIV

• Tears

• Saliva

• Mosquito or insects

• Swimming pool

• Food handling

Highly Active Antiretroviral Therapy (HAART)

Cocktail Therapy

Examples of anti-retroviral drugs

• Cocktail Drug Mixtures

– Protease inhibitors

– Non-nucleoside RT Inhibitors (NNRTIs)

– Nuleoside/nucleotide RT inhibitors (NRTIs)

– * Fusion Inhibitors *Fuzeon

– Integrase Inhibitors

Fusion Inhibitors block

• Co-receptors on host cell

• Gp120/gp 41 on viral particle

or

Co-Receptors

CCR5 or CXCR4 (fusin)

Binds naturally occurring chemokines

Prevention

• Condoms

• Clean needles

• Treatment of pregnant mother with anti-viral drugs

• Blood screening

• Abstinence

Acquired Immunodeficiency Disease

Symptoms of AIDS

• Decrease T cell count

• Rapid weight loss

• Recurring fever and dry cough

• Profound fatigue

• Swollen lymph glands

Symptoms of AIDS

• Persistent diarrhea

• Unusual blemishes on the tongue, mouth, or throat

• pneumonia

• memory loss, depression

Acquired Immunodeficiency Syndrome

Opportunistic Diseases and cancer

• pneumonia

• Kaposi’s Sarcoma Kaposi’s Sarcoma

HIV Diagnostic Tests

• ELISA

Indirect evidence of HIV exposure

measu

res

HIV Diagnostic Tests

• Western Blot

• PCRDirectly measures HIV

Polymerase Chain Reaction• Measures proviral DNA within the host DNA

Western BlotIdentifies HIV proteins

Protein ladder

• A diagnostic test for Antibodies to HIV

Enzyme Linked Immunosorbent Assay

(ELISA)

Antibodies

Antibodies are proteins produced by our immune system that are directed

against specific antigens.

Antibodies Antigens

Immune system Non-self

Now apply these concepts to the diagnostic test known as ELISA to detect antibodies against HIV from a biologic

fluid.

Do any of these individuals carry antibodies to HIV?

ELISA MICROTITER PLATES

Microtiter plate

The ELISA protocol

1

23

4

antigen

sampleLabelled 2nd Ab

Color inducing substrate

Results

POSITIVE ANTI-HIVCOLOR CHANGE

NEGATIVE ANTI-HIVNO COLOR CHANGE

FDA Approves Saliva OraQuick Rapid Test for HIV-1, HIV-2

Antibodies[March 29, 2004]

(similar test is also available for blood samples, see next slides).

OraQuick Rapid Anti-HIV Blood Test

1 2

3 20 minute testCost app. $15.00

Onto the ELISA lab

For Your Information and Files

Acquired Immunodeficiency Syndrome

• Normal CD4+ count

• Normal CD4+ (%)

• AIDS

• 500-1600/mm3

• 20-40%

• <350/mm3 begin anti-viral treatment

• <14% serious immune damage

Table 1. For Your personal Information: not for lecture.Antiretroviral Agents 

 

Agent Type Dose Major Toxicities

AZT NRTI 300 mg bid nausea, headache,  low blood counts

ddI NRTI 125-200 mg bid or 250-400 mg qd(tablet form)

diarrhea, pancreatitis,  peripheral neuropathy

ddC NRTI 0.750 mg tid diarrhea,  peripheral neuropathy

d4T NRTI 30-40 mg bid abnormal liver function tests,peripheral neuropathy

3TC NRTI 150 mg bid minor

abacavir NRTI 300 mg bid hypersensitivity reaction

tenofovirNRTI (nucleotide)

300 mg qdnausea, diarrhea, vomiting, flatulence

AZT/3TC (Combivir)

NRTI one pill bid(300 mg AZT/150 mg 3TC)

see above

AZT/3TC/abacavir(Trizivir)

NRTI one pill bid(300 mg AZT/150 mg 3TC/300 mg abacavir)

see above

nevirapine NNRTI 200 mg bid rash

delavirdine NNRTI 400 mg tid rash

efavirenz NNRTI 600 mg qhs rash, dizziness, impaired concentration, insomnia, abnormal dreams

saquinavir(Fortovase)

PI 1200 mg tid diarrhea

ritonavir PI 600 mg bid nausea/vomiting, drug interactions

indinavir PI 800 mg tid kidney stones

nelfinavir PI 750 mg tid or 1250 mg bid

diarrhea

amprenavir PI 1200 mg bidnausea/vomiting,  diarrhea, rash

lopinavir/ritonavir

PI three capsules bid(133.3 mg lopinavir/33.3 mg ritonavir)

diarrhea, nausea, weakness, headache

Experimental drugs are italicized, and approved drugs are in regular, non-italicized type)

Brand NameGeneric Name Abbreviation Experimental Code Pharmaceutical Company

Fuzeon™ enfuvirtide ENF T-20 Trimeris and Hoffmann-La Roche

      BMS-488043 Bristol-Myers Squibb

      GSK-873,140 GlaxoSmithKline

      PRO-542 Progenics Pharmaceuticals

      SCH-D Schering-Plough Corporation

      TNX-355 Tanox and Biogen Idec

      UK-427,857 Pfizer

Interesting links on HIV

• http://www.niaid.nih.gov/factsheets/aidsstat.htm– Links to global and US HIV/AIDS statistics

• http://www.avert.org/pregnanc.htm– Links to HIV and pregnancy as well as numerous other links

including statistics on global epidemic; HIV/AIDS quizzes and treatment.

• http://www.cdc.gov/hiv/pubs/facts/transmission.htm– Links to CDC and a comprehensive fact sheet on HIV transmission

Experimental drugs are italicized, and approved drugs are in regular, non-italicized type) Brand NameGeneric NameAbbreviationExperimental Code Pharmaceutical Company Fuzeon™enfuvirtideENFT-20Trimeris and Hoffmann-La Roche    BMS-488043Bristol-Myers Squibb   GSK-873,140GlaxoSmithKline   PRO-542Progenics Pharmaceuticals   SCH-DSchering-Plough Corporation   TNX-355Tanox and Biogen Idec   UK-427,857Pfizer What are Entry Inhibitors (including Fusion Inhibitors)?Entry inhibitors work by preventing HIV from entering healthy T-cells in the body. They work differently than many of the approved anti-HIV drugs – the protease inhibitors (PIs), the nucleoside reverse transcriptase inhibitors (NRTIs), and the non-nucleoside reverse transcriptase inhibitors (NNRTIs) – which are active against HIV after it has infected a T-cell. Entry inhibitors work by attaching themselves to proteins on the surface of T-cells or proteins on the surface of HIV. In order for HIV to bind to T-cells, the proteins on HIV's outer coat must bind to the proteins on the surface of T-cells. Entry inhibitors prevent this from happening. Some entry inhibitors target the gp120 or gp41 proteins on HIV's surface. Some entry inhibitors target the CD4 protein or the CCR5 or CXCR4 receptors on a T-cell's surface. If entry inhibitors are successful in blocking these proteins, HIV is unable to bind to the surface of T-cells and gain entry into the cells. Only one entry inhibitor has been approved by the U.S. Food and Drug Administration (FDA): Fuzeon™ (T-20). This drug targets the gp41 protein on HIV's surface. Some experimental drugs target proteins on T-cells: BMS-488043 targets the gp120 protein, PRO-542 and TNX-355 target the CD4 protein, and SCH-D, GSK-873,140 and UK-427,857 target the CCR5 protein. HIV-positive people who have become resistant to PIs, NRTIs, and NNRTIs will likely benefit from the entry inhibitors because they are a different class of drugs. This is good news for HIV-positive people who have tried and failed many of the currently approved anti-HIV medications.To learn more on how HIV infects a T-cell and begins to create more viruses, and where each class of anti-HIV drugs blocks this process, click on the following lesson link:

The HIV Life Cycle (and the targets of each class of anti-HIV drugs)