Since we spent a great deal of time in class this week talking about vaccines, I thought I would post a blog post related to vaccine development. HIV is notoriously known for being able to evade the immune system, making vaccine development very complicated for this virus.
The concept behind vaccine-induced immunity is to expose the immune system to a weakened form of the virus before it encounters the virus in a more potent form. This has proven to be quite difficult for HIV, but researchers at Harvard are in the midst of discovering another way to bolster immunity to HIV.
Drs. Cowan and Rossi from Harvard's Department of Cell & Regenerative Biology have taken an alternative spin on the concept of immunity against HIV. We've talked about the Berlin patient in class, related to the individual who was "cured" of HIV due to a stem cell transplant from a CCR5- donor. Their labs have developed a method to use CRISPR (cluster regularly interspaced short palindromic repeats) editing to target specific parts of the genome of human blood stem cells. They used this technology in two ways -- to edit out the CCR5 gene from human blood stem cells or to effectively "delete" the HIV genes inserted into the genome of cells.
The success of this project has opened up the door to potential therapies in the future.
In particular, editing out the HIV genes from infected patients could potentially eliminate the infection from their stem cell line. This could be done through sampling the patients' blood, using CRISPR to edit out the gene, and then transplanting these cells back to the marrow, allowing the blood cells to repopulate. This research still has many steps to undergo before it can be transformed from bench to bedside, but it has the potential to transform therapeutic techniques for HIV.