Treating HIV with Azidothymidine (AZT)

A Design by Jeanine Nasser

HIV (Human Immunodeficiency Virus): an infection that weakens the human body’s immune system by destroying important cells that fight disease and infection (T-helper cells)

AIDS (Acquired Immunodeficiency Syndrome): the most advanced stage of the HIV virus; a complex illness with a wide range of complications and symptoms

Background Information

More than 25 million people are now living with HIV

In 2013, an estimated 2.1 million people were affected with HIV, 1.5 million of whom were from Sub-Sahara Africa

Everyday more than 5,700 people contract HIV

Around 12.9 million people living with HIV (37% of the total) had access to antiretroviral therapy

(Stats from amtAR-2013)

Statistics

At the moment, there is no preventive vaccine available and treatment is unaffordable for people who need it

Treatment is the most feasible approach to reverse and ultimately halt the HIV epidemic

HIV is a preventable disease; effective HIV prevention interventions have been proven to reduce HIV transmission

PurposeWhy is HIV Prevention

Important?

Although there is no cure for HIV, physicians prescribe combinations of different medications (“cocktails”) that indirectly affect the HIV virus by targeting and strengthening the body’s immune system However, there are a few disadvantages to

taking these cocktails: They’re expensive They must be taken throughout one’s lifetime They’re not easily accessible They can cause some discomforting side effects

Treatment

1. Binding (Attachment): HIV binds to the receptors on the surface of a CD4 (T-helper) cell

The HIV Life Cycle

2. Fusion: The HIV envelope and the T-helper cell membrane fuse, which allows the HIV to inject its viral core containing RNA

The HIV Life Cycle

3. Reverse Transcription: Once inside the T-helper cell, HIV releases reverse transcriptase. HIV uses reverse transcriptase to convert its genetic material (HIV RNA) into HIV DNA

The conversion of HIV RNA to DNA is necessary so that the HIV can enter the nucleus of the T-helper cell and combine with the cell’s DNA

The HIV Life Cycle

4. Integration: HIV produces integrase (enzyme), which allows the HIV DNA to enter the T-helper cell nucleus. Once inside the cell nucleus, the HIV DNA is joined with the T-helper cell DNA

The HIV Life Cycle

5. Transcription and Translation: Once HIV is integrated into the t-helper cell DNA, the virus begins to use the protein-making mechanisms of the t-helper cell to create long chains of HIV proteins, which are the building blocks for making more HIV

The HIV Life Cycle

6. Assembly: Protease (an HIV enzyme) cuts up the long chains of HIV proteins. The smaller HIV proteins combine with HIV RNA to form a new virus

The HIV Life Cycle

7. Budding: Newly made HIV pushes out from the T-helper cell

The HIV Life Cycle

To disturb the reverse transcription phase of the HIV

life cycle to prevent the formation of viral DNA

Objective of My Design

What is AZT?AZT: Azidothymidine

How does it inhibit reverse transcription?

• AZT is a nucleoside reverse transcription inhibitor (NRTI), meaning that when it is incorporated into a DNA template during reverse transcription, it is confused for one of the original nucleotides in DNA (in this case, thymidine)

• Because AZT lacks a 3’ hydroxyl group, the DNA chain cannot be extended, making AZT a chain terminator

What makes it an effective reverse transcription inhibitor?

• If the AZT is released, it can selectively inhibit the HIV’s reverse transcriptase, as reverse transcription is necessary for production of HIV’s double-stranded DNA to subsequently be integrated into the genetic material of the infected cell.

Mechanism of Design1. Receptors on cell membrane activate promoter

of first device in indication of presence of gp120 protein

2. Gene injected with AZT releases AZT3. To indicate that AZT released, a second

promoter is activated4. If AZT is present, glowing fluorescent protein

(GFP) is released Presence of gp120 Release of AZT GFP Glows

1 1 1

0 0 0

Advantages & Disadvantages

Advantages

1. Easily accessible

2. Affordable

3. Permanent effect

Disadvantages

1. Potential overdose of AZT, as

there is no negative feedback

2. Some patients may not

respond to the vaccine

Testing

The effectiveness of the system would be tested

by first taking a blood sample from a patient with

the HIV virus. The bacteria is then inserted into

the blood sample. Once the bacteria is in the

presence of the HIV virus, it can then be

determined whether the system is functioning

properly by observing the change in the color of

the system (i.e., if it glows green or of it does

not).