Author: Hanah Gomberg
Editors: Kira Tian and Liane Xu
Artists: Tiffany Chen
The HIV virus was first isolated and identified in 1983 by scientists at the Pasteur Institute in France. Through the use of techniques in use prior to the HIV epidemic, researchers were able to culture T cells from lymph node biopsies from a 33-year-old French patient with symptoms that preceded AIDS, such as lymphadenopathy.
Falling under the category of “retrovirus”, HIV is an RNA virus. Rather than carrying DNA, retroviruses carry single-stranded RNA in their genetic material. Retroviruses are also able to reverse transcriptase, which enables them to copy RNA into DNA and are used to perform mitosis and infect host cells.
But what exactly is an RNA virus? An RNA virus has ribonucleic acid in its genomes. This acid tends to be single-stranded (ssRNA), but some are double-stranded (dsRNA). The international committee on taxonomy of viruses has classified RNA viruses to belong to one of four groups: Group VI, Group IV, Group VII or Group V. Examples of RNA viruses are Orthomyxoviruses, Hepatitis C Virus (HCV), Ebola disease, SARS, influenza, polio measles. Additionally, common retroviruses are adult Human T-cell lymphotropic virus type 1 (HTLV-1) and human immunodeficiency virus (HIV).
The HIV virus is transferred to the host cells by attaching and fusing with them. Then, the viral RNA genome is reverse-transcribed into double-stranded DNA (dsDNA) through virally encoding reverse transcriptase, along with the viral genome, into the virus-cell. The HIV-infected cells then multiply and attempt to attack other cells. To infect the host cells, the HIV protein envelope (Env) bonds with the primary cellular receptor CD4 and a cellular coreceptor. This sequence of bonds triggers the fusion of the host cell membranes and the viral cells, which begins the infectious process. The HIV virus is then able to infect cells when they are sexually transmitted from one person to another when a person infected by HIV passes their fluids directly into another person’s bloodstream.
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