HIV in the Body and the Effects of the Disease
HIV infection begins when the human immunodeficiency virus (HIV) is transmitted through contact with infected body fluids, often during sex. The virus targets the immune system itself, invading T helper cells; white blood cells that ordinarily fight infection. First, the virus attaches to the cell, injecting its genetic blueprint—contained on viral RNA wrapped in protein shells—into the cell. Viral RNA uses an enzyme, reverse transcriptase, to make viral DNA. The DNA enters the T cell’s nucleus, hijacking the cell’s replication machinery and quickly making numerous copies of the virus.
How Cell Blockers Work
There are numerous drugs to control HIV infection and replication. Overall, these drugs are called antiretroviral drugs. (HIV is a type of virus known as a retrovirus.) One class, known as cell blockers, entry inhibitors, or fusion inhibitors, works by preventing the virus from entering the host cell. By preventing binding, fusion, and entry, these drugs prevent the HIV virus from replicating, or making more copies of itself. They also prevent the destruction of targeted cells, which preserves immune system function. However, eventually the virus may develop resistance to individual drugs.
How Protease Inhibitors Work
Protease inhibitors are another important class of antiviral drugs. They work inside infected immune system cells to prevent the HIV virus from making functional copies of itself. The drugs work by blocking a viral enzyme, protease. Protease works like a pair of microscopic scissors, snipping strands of newly-minted precursor protein into smaller, active viral protein units. Without these tailored protein units, the virus is unable to repackage its genetic material; it cannot complete the process of generating new virus copies capable of infecting other immune system cells.
More than 20 drugs are approved for HIV therapy, with more under development. Today, most people infected with HIV will never develop AIDS, due to use of a “cocktail” of antiviral drugs. This approach is called highly active antiretroviral therapy (HAART). It involves giving patients several drugs at the same time, on an ongoing basis. HAART combines two or more of the following classes of drugs: entry blockers, reverse transcriptase inhibitors, integrase inhibitors and protease inhibitors. By impeding the virus at various stages, HAART boosts T cell counts and the immune system remains strong.
Learn More About Living With HIV
In the United States, more than one million people are currently living with human immunodeficiency virus (HIV). Over the past 30 years, much of the stigma and misconceptions around the disease have disappeared. Better information and education have helped more people better understand the disease, the people who have it, and the changes those people must make because of their diagnosis.