The relationship between CCR5 gene and resistance to cellular HIV infection
The human immunodeficiency virus is the lentivirus and one of the member of retroviridae family On the genatic basis of the viral antigen HIV classified into two major types HIV_1 AND HIV_2 , HIV-1 is the most important type ; HIV-2 is a variant that originated in West Africa and has spread to Central Africa, Europe and South America (1 ) There are many route for transmission of HIV one of them is by sexual intercourse: male to female and female to male. Or can be transmitted from mother to fetus through the placenta, during delivery or by breastfeeding , IV drug abusers , for example by multiple use of needles for injection of drugs, also transmits HIV. The virus can be enter the cells by binding (glycoprotein of 120 kDa) which is surface molecule for HIV to CD4 on T_helper cells and macrophages . also required a coreceptor for infection of target cells: the co receptor for T cell is CXCR4; while the co receptor for macrophage is CCR5 . Viral gp41 fuses with the membrane of the cell and injection into the target cell of two strands of viral genetic information , which is RNA.
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The (CCR5) is expressed on potential human immunodeficiency virus (HIV) target cells and serves as the predominant co-receptor for viral entry during initial transmission and through the early stages of infection. A homozygous D32 mutation in the CCR5 gene prevents CCR5 cell surface expression and thus confers resistance to infection with CCR5-tropic HIV strains. Berlin patient is the first patient who's cured from HIV by transplanting a bone marrow with mutation CCR5 delta 32/ delta 23 Therefore, intense work is currently being carried out on CCR5 geneediting tools to develop curative HIV therapy.
