Instead of an HIV Vaccine, What About HIV Gene Therapy?

By Veronique Greenwood | December 1, 2011 4:28 pm


Vaccines usually work by getting the body to make antibodies against a virus, so when the virus appears on the scene, the immune system is prepared to tag it for destruction. But getting the body excited about making such antibodies isn’t always easy. It’s this stumbling block that has made HIV vaccines so disappointing so far, and in response, some scientists have reached for the big guns of biology. In a paper published today in Nature, one team reports that they’ve been able to make mice immune to HIV using, of all things, gene therapy.

Best known as a process for replacing faulty genes with fresh ones to treat chronic diseases, gene therapy seems, at first glance, like overkill. It involves engineering a lab-grown virus to permanently insert a gene into a patient’s genome, and it can be dicey, to say the least. Despite two decades of research, no gene therapy treatments have made it out of clinical trials. But given the difficulty of getting the immune system to buckle down and make antibodies against HIV on its own, using gene therapy starts to make a kind of sense.

In this study, the researchers have gotten mice susceptible to HIV to produce an antibody against it—not by getting the immune system to kick in, but by giving them a single injection of lab-grown virus carrying the gene for the antibody. The gene was inserted into a group of muscle cells, which manufactured the antibody and released it into the bloodstream. When the researchers dosed the mice with HIV, the antibodies kept the virus from infecting cells, even when the team administered a ridiculous amount of virus, more than 100 times what was required to take down control animals. The gene therapy injection had the protective effects of a vaccine, without needing the immune system to do the heavy lifting.

Humans, of course, are not mice, and it’s notoriously difficult to get gene therapy treatments into the clinic. But this is a creative take on a tough problem. It’ll be interesting to see where the idea goes from here.

Image courtesy of C. Goldsmith / CDC

CATEGORIZED UNDER: Health & Medicine, Top Posts
  • Diana

    Why would gene therapy be effective? If I’m not wrong, HIV’s surface proteins change shape every now and then. Doesn’t this make targeting them via antibodies especially tough?

  • Angie

    This is awesome! Even though it might be hard to get the gene therapy done I still think this is very possible. Maybe within the next 10 years or so if scientists still keep working on this gene therapy, they’ll be able to use it on humans.

  • Andrew

    I’m with Dianna. Seems the gene would become obselete when the virus mutates again.

  • Andrew

    I agree with Diana. Surley the gene would be obselete as soon as the HIV mutates.

  • Jehan

    Many people are leery of bioengineered (genetically modified )foods. The Europeans banned them. But here we have people who want to bioengineer … people! And this is all for a disease that is totally preventable without any drugs. We could wipe out the pandemic solely by behavior modification. Instead it urged that we overthrow the whole cosmos to benefit one small group of people. Before penicillin people coped with the syphilis epidemic in Columbian Europe with behavior modification. They became prudish. As a result the disease mutated & became less virulent. When the disease 1st hit flesh literally fell off people. the change in social mores by enough people put a severe stress on the syphilis that cause certain stain to die out. We can end AIDS in 2o years without spending more money if we just accept monogamy.
    But to delay gratification is anathema now isn’t it.

  • Jeff

    the idea is to use recently identified neutralizing antibodies that react against the many different strains of HIV that are floating around in the world. Because the virus evolves within a given patient it is difficult to design a vaccine that will make antibodies that can block the many slight variations of HIV that might come from different individuals. If the antibodies serve their purpose then you don’t have to worry about the virus mutating because it will prevent HIV from taking hold in the patient and acquiring mutations to evade antibody mediated protection.

    The real concern here is whether free virions (that is HIV that exists in the blood or semen outside of an actual carrier lymphocyte or antigen presenting cell) is the primary culprit for causing new infections. Work from the same group that published this story indicates that most HIV infection occurs from direct cell to cell transmission making an antibody based approach obsolete (since the antibodies don’t enter into live cells and thus would not be able to block an infectious virus unless it is floating outside of the cells.

    Nonetheless the idea is very interesting and I hope that we will see this tested very soon in non-human primates or in human clinical trials.

  • http://DiscoverMagazine Templar 7

    All I know is that I know someone who has had HIV for 35 years now, and is still fully functional and in full health. There is probably thousands of strains of HIV, and in a way it each individual case is it’s own strain.

  • haversham

    Yes, although this is a potential cure and not just beating the virus back with drugs. If the body is actively making antibodies, you could feasibly reduce the viral load to almost nothing. Pair this treatment with a round of antivirals and it becomes even more feasible. Less HIV flare ups within the body generally leads to a longer life expectancy. Even if a gene therapy has to be made for each individual person, would they be willing to pay the necessary 10 to 15 thousand dollars to prolong their life by years? My guess would be yes.

  • TheCritic

    The reason such a “vaccine” would work is different than why regular vaccines won’t. Antibodies floating through the blood stream are much more available than B and T cells and macrophages. If the antibodies cover the virus (opsonization) before it can get to the T cells it affects (by way of inserting itself into the cell through attachment to certain a certain cell receptor that most HIV strains use) then the virus would not be able to enter the cell. Sure, the different strains mutate quite frequently in the body, but they must actually enter a cell and reproduce to mutate. HIV doesn’t just float around and suddenly change its RNA.

    As far as to someone who has had it for 35 years now and in full health. That isn’t evidence for thousands of strains. There are only four that are known to be common. Of these 4, it is not UNcommon for their to be some level of resistance to two of them. This is the idea behind some genetic therapy to give people a certain mutation that alters the T-cell receptor HIV uses to get into the cell. People with this mutation can be exposed to HIV and remain uninfected.

    What’s important when analyzing research like this is not in looking for ways in which it shouldn’t work. The research shows it was effective, so giving reasons as to why it shouldn’t be effective is fruitless.


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