A HIV positive man received a bone marrow transplant, a procedure that transfers blood stem cells from a donor to their own bone marrow due to diseases that affect the blood or bone marrow. In roughly two years, there was nearly no trace of HIV in the man's body. The donor of the bone marrow was discovered to have two copies of the genetic mutation 'delta32' (gene CCR5) that rendered the protein covering of white blood cells appear 'missing' to the HIV virus. The HIV virus replicates itself by fusing with the cell via accumulating proteins on the membrane of the cell, but with the covering missing, the HIV virus is unable to replicate itself. Gero Hütter (head of the team that treated the man) proposed a method that involved finding people with the same delta32 mutation and performing the same bone marrow transplant procedure. The results showed that these defective cells effectively adjusted to the new immune system of the patient, proving its resistance.
Sangumo Biosciences has imitated a trial to begin producing man-made versions of enzymes named zinc finger nucleases (ZFN's) that are tailored to disrupt specified genes, namely, CCR5. The proposed procedure is as follows: take blood samples from a number of patients and remove CD4 cells (cells that are receptors to HIV virus). Add a programmed virus with the coding for ZFN, which will then code the CD4's to produce them and thus, change the CCR5 gene. The new CD4's will become the dominant CD4 cells, which was the result of a successful experimental trial in mice. It may even be possible to use engineer an existing stem cell (CD34) to create HIV resistant white blood cells, but whether the patient's existing bone marrow will have to be destroyed or not has yet to be answered.
Another study performed by Ronald Mistsuya involved coding a virus carrying ribozyme (enzyme that 'snips out' specific genetic material) to eliminate the HIV virus's ability to replicate itself. Then, half of CD34 samples taken from patients were exposed to ART and the ribozyme. The experimental trial showed positive results but the stem cells did not last enough.
The previous two studies have paved way for a new approach by John Rossi, which incorporates three genes (the CCR5 gene mutation and two to disable HIV) in blood cells via CD34. This study is currently underway and being monitored. So far, HIV concentrations are low while patients are on ART.
Overall, both bone marrow transplants and gene therapy has yet to be perfected in the fight against HIV. But in the future, the chances of a successful HIV virus vaccine looks promising.
ID: 42049979, Original Article, Picture source.
Sangumo Biosciences has imitated a trial to begin producing man-made versions of enzymes named zinc finger nucleases (ZFN's) that are tailored to disrupt specified genes, namely, CCR5. The proposed procedure is as follows: take blood samples from a number of patients and remove CD4 cells (cells that are receptors to HIV virus). Add a programmed virus with the coding for ZFN, which will then code the CD4's to produce them and thus, change the CCR5 gene. The new CD4's will become the dominant CD4 cells, which was the result of a successful experimental trial in mice. It may even be possible to use engineer an existing stem cell (CD34) to create HIV resistant white blood cells, but whether the patient's existing bone marrow will have to be destroyed or not has yet to be answered.
Another study performed by Ronald Mistsuya involved coding a virus carrying ribozyme (enzyme that 'snips out' specific genetic material) to eliminate the HIV virus's ability to replicate itself. Then, half of CD34 samples taken from patients were exposed to ART and the ribozyme. The experimental trial showed positive results but the stem cells did not last enough.
The previous two studies have paved way for a new approach by John Rossi, which incorporates three genes (the CCR5 gene mutation and two to disable HIV) in blood cells via CD34. This study is currently underway and being monitored. So far, HIV concentrations are low while patients are on ART.
Overall, both bone marrow transplants and gene therapy has yet to be perfected in the fight against HIV. But in the future, the chances of a successful HIV virus vaccine looks promising.
ID: 42049979, Original Article, Picture source.
