Question

HIV/AIDS

                 Why do some HIV infected individuals (nonprogressors) never develop AIDS?

                 Role of CTLs in HIV infection

                 How does HIV decrease T cell counts so dramatically?

                 Macrophages as a reservoir of HIV in infection

                 HIV vaccine: design and ethics

                 HIV immune evasion and problems for treatment/vaccine

                 Immune evasion of HIV

                 AIDS dementia

                 Perinatal HIV transmission

Answer 1

1) entry of HIV in CD4 T cell mediated by various receptor and co receptor.

CD4 act as a recptor

CXCR5, CCR4 are the coreceptor which mediate the entry of HIV virus in to CD4 T cell. Hene code for CCR5 receptor is CCR5 gene is located on the short (p) on chromosome 3. HIV use the CCR5 receptor, this is essential for their entry in to CD4 T cell. But Some people have the Delta 32 mutation which cause deletion of the portion of the CCR5 gene. People having homozygous mutation of this gene are resistant HIV-1 infection.

2) CTLs play an important role in controlling HIV infections in the person. Cytotoxic T cell ( CD8 T cell ) . CtL cell work against the infected cell cause killing of these cell and regulate infection in the body.  

3) HIV enters in to the Th cell using CD4 receptor. After enter in to the cell , it integrate its genome in to T cell genome. As T cell genome divides, viral genome also divide and packaged in to oral particles. These viral particles are released by the process of budding formation on Th cell membrane. During this process, it stimulate lysis of Th cell and cause decreased Th cell count in blood.

4) macrophages known as reservoir of HIV . Because once HiV enter in to the macrophages its insert its genome in to macrophages genome . And this macrophages enter in to resting stage .like CD4 T cell , entry of HIV does not kill macrophages by direct lysis, and because virus remains safe in infected macrophages as the macrophages are relatively insensitive to antiretroviral agents. So HIV remains as dormant form in macrophages and these cell act as reservoir of the virus.

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