New Antibody Therapy May Suppress HIV

The fight against AIDS may have just gotten some help, as a new antibody therapy developed by scientists may suppress the HIV infection that causes it, according to new research.

In the first human study ever conducted on HIV patients, involving a new generation of so-called broadly neutralizing antibodies, Rockefeller University researchers have found the experimental therapy can dramatically reduce the amount of virus present in a patient's blood. The results, published in the journal Nature, are opening new doors in the field of HIV immunotherapy and suggest new strategies for fighting or even preventing the fatal HIV infection.

When a person is infected with HIV, there is an ongoing battle in their body between the virus and their immune system. Even antibodies produced specifically to target and kill the virus cannot stop it from spreading, as HIV is constantly mutating and staying one step ahead.

However, this new study finds that administration of a potent antibody, called 3BNC117, can catch HIV off guard and reduce viral loads. Until now, HIV antibodies previously tested in humans were unsuccessful. But 3BNC117 belongs to a new generation of broadly neutralizing antibodies that potently fight a wide range of HIV strains.

"What's special about these antibodies is that they have activity against over 80 percent of HIV strains and they are extremely potent," Marina Caskey, one of the researchers, said in a statement.

3BN117 was originally isolated by Johannes Scheid in the Nussenzweig laboratory, and targets the CD4 binding site of the HIV envelope - the primary site of attachment of HIV to host cells.

Amazingly, during these HIV patient trials, 3BNC117 showed activity against 195 out of 237 HIV strains.

Believe it or not, broadly neutralizing antibodies like 3BNC117 are produced naturally in some 10 to 30 percent of people with HIV - but only after several years of infection. By that time the virus has evolved to escape even these powerful antibodies. But researchers have figured out how to isolate and clone these antibodies so they can be used as therapeutic agents against HIV infections sooner rather than later. While animal models had indicated that these antibodies were effective against HIV, this is the first time it has been demonstrated in human patients.

At the highest dosage level tested in the study (30 milligrams per kilogram of weight), all of the infected individuals treated showed up to 300-fold decreases in the amount of virus measured in their blood - raising hope that an HIV vaccine may be in the near future.

In a time when antibiotic resistance is becoming a global problem, it should be noted that in half of the individuals receiving the highest dose, viral loads remained below starting levels even at the end of the 8-week study period and resistance to 3BNC117 did not occur.

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