What is AIDS? Types of Opportunistic Infections A Brief History of AIDS AIDS in Canada Biotechnology and AIDS Prevention Biotechnology and AIDS Diagnosis Biotechnology and AIDS Treatments The Buzz: AIDS Research and Biotechnology Bibliography

What is AIDS?

Acquired immune deficiency syndrome, commonly known as AIDS, is caused by the human immunodeficiency virus (HIV). HIV causes AIDS by disrupting the normal function of the immune system. When HIV enters the body, it attaches to the white blood cells of the immune system, called T-cells. The virus enters these cells and alters their function from fighting disease to producing more HIV. When the disease spreads to other cells and throughout the immune system, the body has a decreased ability to fight off infection.

A person with an HIV infection does not necessarily have AIDS. The immune system can fight an HIV infection for months or years before the disease symptoms become noticeable. However, once the number of T-cells in a person's blood reaches a low of 200 cells/mm3 or an infection develops as a result of his or her weakened immune system, then he or she is diagnosed with AIDS. The deaths associated with AIDS are due to opportunistic infections that the body can no longer fight.

Types of Opportunistic Infections

Opportunistic infections are common infections that a healthy immune system can fight off but pose a threat to people with weak immune systems.

Some of the most common AIDS-associated opportunistic infections include the following:

• Karposi's Sarcoma and other cancers
• Neurological disorders such as dementia
• Bacterial, fungal and parasitic infections
• Viral infections such as hepatitis

A Brief History of AIDS

Although AIDS was not identified until 1982, doctors began to notice what would later become known as symptoms of the disease in 1981.

In 1981, an unusually high number of individuals were diagnosed with a rare form of cancer called Kaposi's Sarcoma, and pneumonia (pneumocystis carinii pneumonia).

In 1982, the reason for the infections was discovered to be an immune deficiency and the syndrome was named AIDS.

In 1986, AIDS-related viruses that had been isolated first in France then the USA were discovered to be the same and given the name HIV.

In the years that followed, the world began to take notice and in 1996 the Joint United Nations Programme on AIDS was formed to unify the efforts of the World Health Organization and other international organizations.

In 1999, only 20 years following the first cases of infection, The World Health Report placed AIDS as the fourth largest cause of death in the world.

AIDS in Canada

In Canada, AIDS was first reported in 1982. By the end of 1999, 16,913 people in Canada had AIDS and 45,534 people had tested positive for HIV. An estimated 4,190 new infections occurred in 1999 alone. Of the total number of people reported with AIDS in 1999, 11,748 have since died.

Biotechnology and AIDS Prevention

HIV Vaccine research is occurring in the following areas:

• Recombinant proteins -- copied proteins from HIV are produced through biotechnology or chemistry. The proteins are then inserted into cells that can present them to the immune system.
  
  
• Live recombinant vectors -- pieces of DNA from HIV are put into an agent such as a proven bacterial vaccine. The bacteria will use the HIV DNA to produce HIV proteins to which the body may build an immunity.
  
  
• Whole inactivated virus -- HIV that has been "killed" so that it no longer functions as a virus (will not produce disease causing proteins) but is still recognized by the immune system.
  
  
• Live attenuated virus -- live HIV that has had its DNA removed or substituted to eliminate the harmful properties, but still capable of stimulating the immune system.

Testing has begun on both HIV positive individuals (for therapeutic applications) and HIV negative individuals (for preventative applications).
Learn more about Vaccines.

Biotechnology and AIDS Diagnosis

Biotechnology makes possible a number of different methods that diagnose and monitor AIDS. Tests can offer positive or negative results to indicate the presence of HIV in a person's blood. They can also give more detailed information, such as the actual amount of virus (viral load) present in a given individual's blood stream. The following are some examples of AIDS diagnostic tools derived from biotechnology:

• Polymerase Chain Reaction (PCR) assay -- The PCR assay is a test that can indicate the viral load in an individual's blood by screening for the RNA of HIV. It uses polymerase, which is the same enzyme that the body uses to replicate DNA. The polymerase reaction assembles the building blocks of RNA to make copies of viral RNA found within a patient's sample. A billion copies of viral RNA can be made in a matter of hours. This rapid amplification allows scientists to identify the presence of HIV and calculate the amount of virus in an individual's blood stream.
  
  
• Enzyme-linked Immunosorbent Assay (ELISA) -- The ELISA test gives simple positive or negative results by screening for antibodies produced by the body after HIV infection. This tool makes use of proteins taken from purified HIV and a colour indicator. A positive result is marked by the presence of colour in the test container, indicating that HIV antibodies from a patients blood sample have bound to HIV proteins in the assay.
  
  
• Western Blot -- The Western Blot test also gives a positive or negative result but it is more accurate than the ELISA and is usually used to confirm positive ELISA results. The Western Blot test uses a number of proteins from HIV that are arranged on a strip of film from smallest to largest. If there are HIV antibodies in a sample of blood serum added to the film then they will bind to the proteins on the strip of film. A colour indicator highlights the antibodies that are bound on the film.

Learn more about these and other Diagnostic Assays.

Biotechnology and AIDS Treatments

Currently, the most commonly used AIDS treatments are enzyme inhibitors. Certain enzymes are required by the virus to advance through the different stages of infection. Most of the drugs in this class are not manufactured through biotechnology. However, the study of genomics has helped lead to their discovery and continues to add insight into issues of drug efficacy, resistance, and side effects. Examples of enzyme inhibitors are:

• Reverse transcriptase and protease inhibitors -- Reverse transcriptase inhibitors prevent HIV from copying its genetic information (RNA) into DNA, which can then be inserted into the host's cell genome. Protease inhibitors prevent HIV from assembling new copies of itself within the infected cell. Both of these inhibitors are currently available and many more are under study.
  How do Viral Enzyme Inhibitors work?
  
  
• Monoclonal antibodies -- Monoclonal antibodies are antibodies produced from clones of a single cell. They all possess the same attraction for a specific target. Monoclonal antibodies can be attached to medications and targeted at diseased tissues such as AIDS related cancers. They can also attract the attention of other immune defences to destroy virus infected cells.
  How do Monoclonal Antibodies work?
  
  
• Interferons -- Interferons are natural proteins produced by the body in response to infection. They stimulate the immune system cells to produce proteins that can block viral infection or act on other diseased tissues (cancerous). Genetic engineering is used to make interferons in the amounts necessary for treatment. Currently, interferons are prescribed to combat opportunistic cancer infections and are under study for the treatment of HIV infection. Interferons belong to a class of immune system proteins called cytokines.
  How do Cytokines work?
  
  
• Liposomes -- Liposomes are a drug delivery system that mimic the cell membranes of the body. A liposome is a small vesicle composed of a lipid (fat) membrane and cholesterol molecules. This structure allows liposomes to transport different types of disease treatments to locations in the body where the treatments normally can not enter. With the addition of specific proteins to the membrane, liposomes can also be directed at a certain type of disease cell such as cancer.
  How do Liposomes work?

Numerous other biotechnology applications for AIDS are in clinical trials or under development.

The Buzz: AIDS Research and Biotechnology

The research surrounding AIDS is extensive and biotechnology has become a tool for the production of many new products. Current research areas are:

• Interleukins -- Interleukins are proteins produced naturally by the body to modulate immune responses. There are many different types. However, interleukin 2 (IL-2) has been getting the most attention. IL-2 could potentially increase the number of T-Cells in HIV positive patients.
  Learn more about interleukins.
  
  
• Integrase Inhibitors -- Integrase is a viral enzyme used by HIV to insert its genetic material into a host cell's genome. This particular enzyme is very complex but biotechnology research is progressing towards creating an inhibitor that will be able to target integrase effectively. Substances under study include organic chemicals and synthesized plant extracts.
  Learn more about integrase inhibitors.
  
  
• HIV genes -- Research into the genetic structure of HIV is showing promise. Genes that code for enzymes and the proteins that coat the virus are all potential targets for drugs. Study of the human genome has revealed genes that code for receptors to which HIV is attracted. Knowledge of both the human and HIV genomes is helping drug developers target the most important proteins involved in HIV infection.
  Learn more about genomics.
  
  
• Stem Cells -- Blood stem cells are located in the bone marrow. They have the ability to differentiate into any type of blood cell including those that function mainly in the immune system. Research is under way to add HIV interfering genes to these stem cells so that they produce blood cells that are resistant to the disease.
  Learn more about stem cells.

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