CERTAIN genes have the ability to provide HIV resistance in some individuals. In 2005 there were 38.6 million people living with HIV, the Human Immunodeficiency Virus (UNAIDS, 2009). HIV finds the correct cells to infect by finding particular proteins called receptors, in this case CD4 cells. These CD4 cells are on the outside of cells and receive incoming information which transmitted into the cell. Cells with these receptors are targeted by the virus and destroyed. CD4 cells work with a co-receptor, a protein named CCR5. Another co-receptor sometimes found is the CXCR4, which HIV can also target. The receptor and the co-receptor work together, and in the case of HIV infection, they allow the virus to enter the cells and slowly destroy the immune system. Figure 1 shows the location of receptor, CD4, and the co-receptors, CCR5 or CXCR4.
A mutation in the CCR5, a co-receptor with CD4 cells, can lead to a resistance to HIV in cells with this co-receptor. The mutation is called CCR5-delta32 and is a similar gene, but the protein is smaller and located inside the cell. With the mutated co-receptor not on the surface of the cell, the virus can’t infect it. About 1% of the Caucasian population has 2 copies of the mutation, inherited from both parents, and are resistance to some strains of HIV. A further 20% of the Caucasian population has 1 copy of the mutation, giving them some protection and can decrease the severity of the virus.
Some types of the Human Immunodeficiency Virus use different proteins for entering the cells, such as the CXCR4, mentioned previously, and thus even 2 copies of the mutated CCR5 doesn’t necessarily mean they are completely resistant and protected from the virus.
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DR. KIMMEL, Robin. "The Evolving Genetics of HIV: Can Genes stop HIV?." Understanding Genetics: Human Health and the Genome. 29 Mar. 2009 (www.thetech.org/genetics/news.php?id=13).
UNAIDS. "AIDS: 2. What are the worldwide trends in the HIV/AIDS epidemic?." GreenFacts - Facts on Health and the Environment. 28 Mar. 2009 (http://www.greenfacts.org/en/aids/l-2/2-hiv-aids-statistics.htm).
