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  • AIDS HIV Terms
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• AIDS HIV Terms

AIDS-HIV Related Terms

- V -

• V3 Loop

Section of the gp120 protein on the surface of HIV. Appears to be important in stimulating neutralizing antibodies.



• Vaccination

Inoculation of a substance (i.e., the vaccine) into the body for the purpose of producing active immunity against a disease. See Vaccine.



• Vaccine

A substance that contains antigenic components from an infectious micro-organism. By stimulating an immune response -but not the disease-it protects against subsequent infection by that organism. There can be preventive vaccines (e.g., measles or mumps) as well as therapeutic (treatment) vaccines. See Therapeutic HIV Vaccine; Antigen.



• Vaccinia

A cowpox virus, formerly used in human smallpox vaccines. Employed as a vector in HIV vaccine research to transport HIV genes into the body. See Vaccination; Vector.



• Vaginal Candidiasis

Infection of the vagina caused by the yeast-like fungus Candida (especially Candida albicans). Symptoms include, pain, itching, redness, and white patches in the vaginal wall. It can occur in all women, but it is especially common in women with HIV infection. The usual treatment is a cream applied locally to the vagina. Women with HIV infection may experience frequent re-occurrence of symptoms and may require systemic medications in order to treat these symptoms successfully. See Candidiasis.



• Valley Fever

See Coccidioidomycosis.



• Variable Region

The part of an antibody's structure that differs from one antibody to another.



• Varicella Zoster Virus (VZV)

A virus in the herpes family that causes chicken pox during childhood and may reactivate later in life to cause shingles in immunosuppressed individuals.



• Vector

A nonpathogenic bacterium or virus used to transport an antigen into the body to stimulate protective immunity (e.g., in vaccine).



• Vertical Transmission

Transmission of a pathogen such as HIV from mother to fetus or baby during pregnancy or birth. See Perinatal Transmission.



• Viral Burden

The amount of HIV in the circulating blood. Monitoring a person's viral burden is important because of the apparent correlation between the amount of virus in the blood and the severity of the disease sicker patients generally have more virus than those with less advanced disease. A new, sensitive, rapid test-called the viral load assay for HIV-1 infection-can be used to monitor the HIV viral burden. This procedure may help clinicians to decide when to give anti-HIV therapy or to switch drugs. It may also help investigators determine more quickly if experimental HIV therapies are effective. See Viral Load Test; Polymerase Chain Reaction; Branched DNA Assay.



• Viral Core

Typically a virus contains an RNA (ribonucleic acid) or DNA (deoxyribonucleic acid) core of genetic material surrounded by a protein coat. As related to HIV Within HIV's envelope is a bullet-shaped core made of another protein, p24, that surrounds the viral RNA. Each strand of HIV RNA contains the virus' nine genes. Three of these (gag, pol, and env) are structural genes that contain information needed to make structural proteins. The env gene, for example, codes for gp160, a protein that is later broken down to gp120 and gp41. See Surrogate Marker.



• Viral Culture

A laboratory method for growing viruses.



• Viral Envelope

As related to HIV HIV is spherical in shape with a diameter of 1/10,000 of a millimeter. The outer coat, or envelope, is composed of two layers of fat-like molecules called lipids, taken from the membranes of human cells. Embedded in the envelope are numerous cellular proteins, as well as mushroom-shaped HIV proteins that protrude from the surface. Each mushroom is thought to consist of four gp41 molecules embedded in the envelope. The virus uses these proteins to attach to and infect cells.



• Viral Load Test

Test that measures the quantity of HIV RNA in the blood. Results are expressed as the number of copies per milliliter of blood plasma. Research indicates that viral load is a better predictor of the risk of HIV disease progression than the CD4 count. The lower the viral load, the longer the time to AIDS diagnosis and the longer the survival time. Viral load testing for HIV infection is being used to determine when to initiate and/or change therapy. See Viral Burden.



• Viremia

The presence of virus in the bloodstream. See Sepsis.



• Viricide

Any agent that destroys or inactivates a virus.



• Virion

A virus particle existing freely outside a host cell. A mature virus.



• Virology

The study of viruses and viral disease.



• Virus

Organism composed mainly of nucleic acid within a protein coat. When viruses enter a living plant, animal, or bacterial cell, they make use of the host cell's chemical energy, protein, and nucleic acid-synthesizing ability to replicate themselves. After the infected host cell makes viral components and virus particles are released, the host cell is often dissolved. Some viruses do not kill cells but transform them into a cancerous state. Some cause illness and then seem to disappear, while remaining latent and later causing another, sometimes much more severe, form of disease. In humans, viruses cause measles, mumps, yellow fever, poliomyelitis, influenza, and the common cold, among others. Some viral infections can be treated with drugs.



• Visceral

Pertaining to the major internal organs.