Course of the HIV.
The process if infection.
HIV/AIDS are two different terms used together only to relate the cause to the condition.
HIV stand for Human Immuno Deficiency Virus- it is a retrovirus that infects only the human body finally causing the body's immune system shut down leaving the body defenseless in a condition called AIDS i.e. Acquired Immuno Deficiency Syndrome.
HIV, lets discuss it briefly -
1. H - Human (as the virus affects only human cell)
2. I - immunodeficiency (the virus attacks the immune system and terminates its activity)
3. V - it's a virus( a retrovirus that is very thoroughly multiplicative)
What is a retrovirus?
To understand the definition of retrovirus we must know its composition first:
1. It is a multi enveloped virus. It contains
An envelope derived from host cell membrane
Retroviral protein layer
Capsid protein layer (enclosing the RNA)
GP (Glyco proteins) 120 molecules are viral glycoprotein molecules specific to HIV. They along with bi layer lipids make up the outermost layer derived of the host cell membrane.
2. An RNA fragment inside the Capsid present in a single stranded form.
3. Contains its own enzymes to insert into host cell on infection:
Reverse Transcriptase and Integrase
Thus a Retrovirus is an assembly made to infect the nuclear material of a cell and convert it into its own production factory.
This course of infection (the cell cycle) of the retrovirus is divided into the following stages:
1. ATTACHMENT
The retrovirus reaches its site of infection, a human cell. Where it attaches to the bi layer membrane and invade the cell. Releases the Capsid into the cell
2. UNCOATING
The un coating of the RNA strands present in the Capsid takes place once the Capsid reaches deep into the cell territory releasing active RNA strands.
3. DNA SYNTHESIS
Now by the virtue of the attachment of reverse transcriptase, reverse transcription synthesizes a DNA from the RNA material.
4. INTEGRATION
This DNA integrates with the cell nuclear DNA and starts getting transcripted.
5. TRANSCRIPTION
Transcription of the modified DNA material.
6. TRANSLATION
The transcripted material contains more RNA strands which code for the virus proteins and RNA is translated and materials for a new generation of the same virus are ready.
7. CLEAVAGE
Once these materials form, they start accumulating into composures making it new viral particles in the exact same assembly like the parent.
8. RELEASE
The cleaved cell releases the new retro viruses ready to infect other human cells.
The retroviral infections are severe in more than one way:
- The infection takes a dangerous toll on the number of human cells, causing cell death at a much higher scale.
- Since the infection is inside a human cell, it is not seen by the human immune system, therefore not easily suppressible in the body once the infection onsets.
- The retroviral growth rate is fast, its cell cycle completes in 2-4 hours.
Thus the severity of AIDS lies in the severity of its infection.