HIV has historically been a difficult virus to fight because it weakens the immune system by destroying T-cells. The purpose of these cells is to tell the immune system when to kick in and fight off viruses. HIV uses these T-cells to replicate and kills the T-cells in the process, leaving the immune system defenseless.
Here is a really nice video of HIV Replication from AllThingsScience
There are many different options for treating HIV that target the HIV life cycle, but the development of a means of preventing the initial HIV infection of the cells has been elusive. However, scientists are beginning to use a genome editing technique called CRISPR to cut out specific sections of DNA in the HIV genome.
A hematology professor at the University of California, Yuet Kan, and his team, have engineered induced pluripotent stem cells, or iPSCs that may provide a solution. These cells have been modified with the mutation that has temporarily cured an HIV patient in the past, although the disease later returned. Basically, this mutation disables the receptors (called CCR5) that HIV uses to enter T-cells, and essentially, locks them out. The researchers used CRISPR to cut out part of the DNA sequence in the host cell, and insert the mutation from the HIV-resistant cells. Since these are iPSC cells, they can be induced to form new types of cells, such as white blood cells. The initial research suggest that this is possible, and the hope is that eventually the iPSCs can be reintroduced into the blood-forming bone marrow so that they can produce their own resistant white blood cells. Scientists are hoping to use this method to get away from the repeated transfusions that would be necessary to extract many white blood cells and edit them individually.
- Albert W. Cheng, Haoyi Wang, Hui Yang, Linyu Shi, Yarden Katz, Sudharshan Rangarajan, Thorold W. Theunissen, Chikdu S. Shivalila, Daniel B. Dadon, Rudolf Jaenisch. RNA-guided multiplexed endogenous gene activation. Cell Research (2013) 23:1163–1171. doi:10.1038/cr.2013.122
- Gene editing tool can write HIV out of the picture – New Scientist, June 2014
- AIDS.gov: What is HIV?
- Videos on the CRISPR