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International AIDS Conference reported that every 15~17 minutes there will be a patient die from AIDS.

HIV (Human Immunodeficiency Virus) is the virus that causes AIDS. They enter the human body to kill a white blood cell known as CD4 T-cells and severely damage the normal function of the immune system. But how does HIV work? How does HIV replicated so quickly that kill all the human CD4 T-cells? In this section you will find out.

HIV Structure
How does HIV look like?

HIV consists of a cylindrically shaped nucleoid and the surrounding proteins. They are both enclosed a lipid, fatty, envelope. The nucleoid is composed of two proteins known as Nucleoid Core Protein (p24) and Matrix Core Protein (p17). Inside the nucleoid are Viral Genomic RNA and the associate enzyme called reverse transcriptase (RT). Outside the envelope attaches two proteins known as Transmembrance Glycoprotein (gp41) and Envelope Glycoprotein (gp120). The function of these two outer layer proteins is to enable HIV to bind and fuse with another target cell.

HIV Attacks
How does HIV invades human body?

In order to replicate, HIV cells must convert RNA (ribonucleic acid) into DNA (deoxyribonucleic acid), using a method called reverse transcription. Reverse transcription is accomplished by an important enzyme called RT (reverse transcriptase)
HIV automatically binds any cells that contains CD4 on their outer membranes, such as CD4 T-cells. HIV uses CD4 T-cells as a main receptor to which it attaches. In the above paragraph, you learned that two proteins gp41 and gp120 helped HIV to recognize in order to bind and fuse a target cell. When HIV enters human body, gp120 automatically recognizes and binds CD4, making the virus to fuse with the cell. During fusion, the viral nucleoid in HIV enters the cell. Then, reverse transcription occurs, causing all the viral RNA converted into DNA. Eventually, the viral DNA is transported and inserted into the cell's DNA. HIV then replicates in the process through binary fission, conjugation, or budding.
If you are still confused, think of it in this way: Suppose you have two cups of milk - one plain milk (CD4 T-cells) and one chocolate milk (HIV). You pour some chocolate milk into the plain milk which the chocolate particles enters the plain particles and they mix together. Now you have two cups of chocolate milk. If you perfer, pour these chocolate milks into even smaller cups to increase the amount of cups, as the replication of HIV.

HIV Lifecycle
How does HIV live?

HIV does not survive well outside the human body or in the outside the environment. Therefore, HIV virus does last very long. Through AIDS patient's blood, it contains approximately 10 000 viruses per millimeter. However, laboratory studies have proved that HIV can only survive within one or two seconds. The studies also shown that drying HIV reduces the amount of viral by nearly 95 percent within several hours.