In order for viruses to reproduce, they must infect a cell. Viruses are not technically alive: they are sort of like a brain with no body. In order to make new viruses, they must hi-jack a cell, and use it to make new viruses. Just as your body is constantly making new skin cells, or new blood cells, each cell often makes new proteins in order to stay alive and to reproduce itself. Viruses hide their own DNA in the DNA of the cell, and then, when the cell tries to make new proteins, it accidentally makes new viruses as well. HIV mostly infects cells in the immune system.
Infection: Several different kinds of cells have proteins on their surface that are called CD4 receptors. HIV searches for cells that have CD4 surface receptors, because this particular protein enables the virus to bind to the cell. Although HIV infects a variety of cells, its main target is the T4-lymphocyte (also called the "T-helper cell"), a kind of white blood cell that has lots of CD4 receptors. The T4-cell is responsible for warning your immune system that there are invaders in the system.
Replication: Once HIV binds to a cell, it hides HIV DNA inside the cell's DNA: this turns the cell into a sort of HIV factory.
Definitions
There are a few things you need to know in order to understand HIV infection.
DNA: DNA is like the "blueprint" for building living cells.
Enzymes: Enzymes are like the workers of a cell. They build new proteins, transport materials around the cell, and carry out other important cellular functions.
RNA: RNA is like the construction boss. Cells use RNA to tell enzymes how to build a specific part of a cell. To make a new protein, enzymes will copy a specific part of the DNA into a piece of RNA. This RNA is then used by other enzymes to build a new protein or enzyme.
Proteins: The building blocks that are used to make living things.
Nucleus: A small package inside the cell where the genetic material is kept.
Page 2 of Aids and HIV
Binding
A virus consists of an outer envelope of protein, fat and sugar wrapped around a set of genes (in the case of HIV, genetic information is carried as RNA instead of DNA) and special enzymes.
HIV has proteins on its envelope that are strongly attracted to the CD4+ surface receptor on the outside of the T4-cell. When HIV binds to a CD4+ surface receptor, it activates other proteins on the cell's surface, allowing the HIV envelope to fuse to the outside of the cell.
Entry inhibitors can block entry
HIV's genes are carried in two strands of RNA, while the genetic material of human cells is found in DNA. In order for the virus to infect the cell, a process called "reverse transcription" makes a DNA copy of the virus's RNA.
After the binding process, the viral capsid (the inside of the virus which contains the RNA and important enzymes) is released into the host cell. A viral enzyme called reverse transcriptase makes a DNA copy of the RNA. This new DNA is called "proviral DNA."
AIDS (acquired immune deficiency syndrome) is a condition caused by a virus called HIV. This virus attacks the immune system, the body's "security force" that fights off infections. When the immune system breaks down, you lose this protection and can develop many serious, often deadly infections and cancers. These are called "opportunistic infections" (OIs) because they take advantage of the body's weakened defences. You have heard it said that someone "died of AIDS." This is not entirely accurate, since it is the opportunistic infections that cause death. AIDS is the condition that lets them take hold.
HIV is a virus, like the flu or cold. A virus is really nothing but a set of instructions for making new viruses, wrapped up in some fat, protein and sugar. Without living cells, a virus can't do anything – it is nasima like a brain with no body. In order to make more viruses (and to do all of the other nasty things that viruses do), a virus has to infect a cell. HIV mostly infects T-cells, also known as CD4+ cells, or T-helper cells. These cells are white blood cells that turn the immune system on to fight disease. Once inside the cell, HIV starts producing millions of little viruses, which eventually kill the cell and then go out to infect other cells. All of the drugs marketed to treat HIV work by interfering with this process.
To protect yourself from HIV you should: -
1). Practice safe sex (using kite marked condoms) or celibacy.
2). Cut back on having sex or wait till you are in a permanent relationship.
3). Wipe surfaces with good disinfectant after cleaning up spills of any body fluids.
4). Wear deposable gloves when dealing with blood, body fluids or wounds.
