Authored By: B. V Waghmare

Monday, November 15, 2010

Information on HIV virus

Information on HIV virus, HIV virus infects human , how HIV virus reproduces in number (Replication of HIV virus) 


Give information about HIV virus types
There are two species of HIV virus: HIV-1 and HIV-2.
HIV-1 is the virus that was initially discovered and as both LAV and HTLV-III (Human T-Lymphocytic virus Type iii ). It is considered more virulent and more infective, it is presently the major cause of HIV infections worldwide.


HIV-2 posses lower infectivity than compared to HIV-1 .

Give Brife information on HIV virus morphology( structure)
Structure of HIV virus
HIV virus is spherical in structure , measuring about 120 nm,It consist of two copies of RNA enclosed in to a capcid along with its enzyme system and proteins, the capsid is further surrounded by a lipid membrane made of P17 proteins.This inturn is surrounded by two layers phospholipids fatty molecules called as viral envelop.
There are about 70 protrusions of protiens from HIV virus envelop, these protrusions consists a tip called as cap and the stem which holds cap firmly placed on viral envelop.
Cap is made from glycoprotein (gp) 120 and stem is made from glycoprotein (gp) 41.These protiens help in attaching virus over t-lymphocytic cells and then injecting its RNA , in to human T lymphocytic cell .

Give Brife Information about Process of HIV virus infection 
Entry of HIV virus in  to cell
HIV virus gain entry in to human cells which are responsible for protecting human body from any form of incoming infection, that is by infecting CD4 T cells and macrophages
The process of gaining entry in to these cells involves adsorption of HIV virus over T cells surface receptor CD4 receptors this process involves adsorption of HIV viral glycoproteins over of lymphocytes , then HIV virus fuses with host cell by fusing its viral envelop with the human cell membrane and then HIV virus releases capsid into the lymphocytic cells.

In first step of HIV virus attachment over human lymphocytic cells , involves formation of bonding with viral protein arms called gp160 proteins with CD4 receptor and chemokine receptors of human lymphocytic cells.
At the same time gp120 proteins arm over HIV virus binds to integrin receptors which are a type of receptors over human cell that regulate attachment of cells with body tissue to facilitate cellular process , these receptors facilitate spreading of cell over the attaching surface , in this case it is HIV virus.

After attachment of gp120 protein arm of HIV virus , lymphocyte cell surface is aligned in proper orientation , so that the N terminal gp 41 protein of HIV virus easily penetrate in to human lymphocytic cell , this interaction or gp41 HIV viral protien facilitate in fusion of HIV viral capcid with human lyphocytic cells.
After fusion of HIV viral capcid , with human lymphocytic cell , HIV viral enzyme systems and HIV viral genetic material that is RNA , is released in to human cell cytoplasm.

While our body cells normal metabolic function RNA of this HIV virus is transcribed in to a single stranded DNA called as cDNA , which in tern is transcribed in to double stranded DNA that is now able to guide human host cell to synthesize HIV viral RNA and its proteins and enzymes which are then organized in to a new HIV virus , this process is called assembly and then this newly formed virus are released in to blood destroying the infected cell.

For this HIV DNA thus formed gets incorporated in to human DNA, and when ever human cell DNA functions normally to synthesize required proteins for human body function , it also synthesize new HIV viral particles by producing HIV viral proteins , RNA and enzyme system.

HIV virus also infect dendritic cells which are present in inner lining of the nose, lungs, stomach and intestines, and blood, and skin their main role is to capture an antigen and take it to lymph node and present this antigen to lymphocytic cells, which in tern result in development of immunity against the antigen.
Fasciculation and elongation protein zeta-1 (FEZ1) found in neurons prevents HIV virus from infecting neurons

Replication and transcription.
Human Imuno deficiency virus knows as HIV virus belongs to the genus Lentivirus, and Family Retroviridae.
HIV virus (Family Retroviridae) is a RNA virus, as against other types of virus which contains DNA .For process of reproduction of virus , it is required that it pass on its genetic information from parent virus to new virus . DNA contains genes, and gens are able to transfer its genetic information from parent to progeny, but HIV contains RNA it stores all genetic information over these RNA.

Hence to transfer its own genetic information from parent virus to new virus, RNA of HIV Virus develops a copy of a DNA, This process is known as reverse transcription, and it is facilitated by enzyme reverse transcriptase, the reverse transcription process and enzyme reverse transcriptase is so called reverse as the process is just reverse process compared to DNA virus, where a genetic information is transcribed from DNA through RNA.

The newly formed single stranded copy of DNA makes its complementary copy and forms a double stranded DNA, with the help of enzymes DNA polymerase.

Now this DNA copy of HIV virus gets incorporated in to human DNA of T-Lymphocytes, and when ever these T-Lymphocytes carry out the process of protein synthesis for them selves, they are also making the HIV virus proteins and RNA as that of parent HIV virus as the DNA of infected T-Lymphocytes contains DNA copy formed by HIV virus in the process of reverse transcription.
The enzyme responsible for integration of DNA copy formed by HIV virus in to human DNA of T-Lymphocytes are intercalase and integrase.

Steps in the HIV Replication Cycle1. HIV virus fusion with the surface of the host cell.
2. Entry of HIV virus RNA, integrase, reverse transcriptase, HIV virus other proteins in to host cell.
3. HIV virus DNA copy formed after action of reverse transcription.
4. Transportation of Viral DNA across human cell nucleus and intergradation in the host DNA.
5. Newly formed HIV virus RNA utilized as genomic RNA for making new HIV virus proteins.
6. Newly formed HIV virus RNA and proteins goes towards cell surface , a new HIV virus which is immature is formed.
7. HIV virus finaly developes in to complete assembly after enzyme protease forms individual HIV proteins.


What is AIDS?
HIV virus is infects human T-Cells which are known to impart immunity and protect human body from any sort of incoming infection, after infection with HIV virus, these cells count lowers down to such an extent that, the general microbial flora which all humans do harbor in their body, and is not harmful otherwise, becomes harmful and turns to be pathogenic (Harmful). This is the main cause which develops serious and life threatening complications in HIV virus infected individuals, thus develops in to the disease known as AIDS (Acquired immune deficiency syndrome).

When do AIDS disease occurs?
When a person is infected with HIV virus, there are chances of developing disease AIDS acquired immune deficiency syndrome. This disease is developed as a result of decline in CD4 cell count (below 200 / ┬ÁL) as HIV virus destroys all of CD4 cells in our body.
Chances of development of AIDS disease can be minimized by starting early anti retroviral drug therapy , early treatment for HIV infection can save life of person to considerable amount of time there are peoples living for more that 15 years and more with HIV positive status , with anti retroviral drug therapy.

There is much more information on HIV virus new findings available on this blog.
Here are given details about symptoms of AIDS , all new symptoms of AIDS and HIV virus infection are updated.

Drug development against HIV virus , Drug Resistance assay's and analysis during drug development


Here is the latest development on treatment for HIV and AIDS
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Source:
Basic information about HIV and AIDS ==>http://www.cdc.gov/hiv/topics/basic/index.htm

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This website provideds complete information about hiv virus , hiv infection , early hiv symptoms , hiv treatment,hiv test and hiv testing centers, aids symptoms, symptoms of hiv immideately after infection.

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Last updated: 15-Nov-2010


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