Clipping of news on Brazilian Culture, Law and Citizenship
25/01/2013
This article was translated by an automatic translation system, and was therefore not reviewed by people.
Through genetic manipulations, scientists have developed in the lab immune cells resistant to HIV. In the future, the efficacy of gene therapy is confirmed in clinical trials, it can eventually replace the cocktail. The strategy involves inserting genes in cells resistant to the virus that are the target of HIV called lymphocytes T.
The discovery, by researchers at the School of Medicine at Stanford University, was published this week in the journal Molecular Therapy, the Nature group. "We inativamos one of the receptors that HIV uses to gain access to the cell and add new genes to protect against the virus, in order to have multiple layers of protection, what we call 'stacking'," says researcher Matthew Porteus, principal author of the study.
The virus enters the port as T lymphocytes using two types of protein which are on the cell surface, known as CCR5 and CXCR4. Without these receptors, the virus is unable to enter. The researchers broke the DNA sequence of the CCR5 receptor and there inserted three genes known to confer resistance to the AIDS virus.
After this real work of "cut and paste" genetic, viral entry into the cell is locked, which would prevent him from destroying the patient's immune system. The researchers note that the therapy would not have the ability to cure the infection, but to reproduce the effect of treatment with the cocktail, with more efficacy and fewer side effects.
The search for a gene therapy against HIV is something that scientists seek for more than 20 years, since the existence of receptors the virus was discovered, according to the infectious disease Kallás Esper, professor of Medicine, University of São Paulo (USP) and member of the Brazilian Society of Infectious Diseases (SBI).
It explains why several groups seeking an effective way to block the CCR5 receptor, as it was found that inactivation does not compromise other body functions. "A person who has no CCR5 does not die, because other proteins replace their paper, there is a significant impairment of health," says Kallás, who adds that a class of anti-HIV drugs in use today have exactly this principle.
Berlin Patient. But what really sparked hope for the success of a gene therapy against HIV was the case of the patient Timothy Ray Brown, American diagnosed with HIV in 1995. While it was the infection, Brown - who lived in Berlin - developed leukemia. His oncologist found a bone marrow donor who had a genetic mutation that naturally protects its wearer against the virus.
"After the treatment ended, he had the pleasant surprise of seeing that has succeeded in curing leukemia, the virus was no longer detected. He is regarded as the single case of HIV cure," says Kallás. From that event, Brown was known worldwide as the "Berlin Patient". His case has opened the door for the old idea that we had to modify the genetics of the patient to try to reproduce the protective effects of this mutation.
According to the doctor Olavo Henrique Munhoz Leite, Coordinator of Reference Unit in Preventable Infectious Diseases, Faculty of Medicine of ABC, it is not known exactly what led to the cure of Brown. "Will worked because the donor marrow was an individual who had the mutation? If we started to get individuals and we did the same procedure, the results would be the same? Chances are that a sum of factors has allowed the cure."
Can not play the strategy that cured the patient in Berlin because the marrow transplant involves many risks. Furthermore, the protective mutation is very rare to be found in marrow donors.
The presence of the mutation in CCR5 Delta 32, which protects against HIV, was discovered in 1996. According Kallás, studies show that it probably arose about 500 years ago in northern Europe. "The theory is that the Black Death also spared the people who had this mutation," he says. It is present in 1% of the European population.
Source: MSN - Estado
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This article was translated by an automatic translation system, and was therefore not reviewed by people.