Scientists are one step closer to developing a vaccine for HIV. The National Institutes of Health issued a press release last Thursday announcing the exciting discovery of two antibodies that were shown in the lab to prevent upwards of 90% of known HIV strains from infecting human cells.
A team of researchers from the National Institute of Allergy and Infectious Diseases (NIAID) Vaccine Research Center (VRC) discovered the antibodies, named VRC01 and VRC02. Details of their findings were published in the online edition of the journal Science.
Developing a vaccine for the HIV virus has been the Holy Grail for researchers since its discovery in 1981. Because the virus constantly mutates, a vast number of variants now exist worldwide. This genetic variability allows the virus to evade recognition by the human immune system and has prevented scientists from creating an effective vaccine.
NIAID researchers first created a unique device from a genetically modified HIV protein that allows them to identify antibodies that target only the specific area of the virus that binds to human cells, called the CD4 binding site.
The CD4 binding site acts like a “lock-and-key” with the CD4 receptor site of healthy immune cells. Since the CD4 binding site remains relatively constant from strain to strain, identifying antibodies that can attach to the binding site is critical to the development of a vaccine.
The naturally occurring VRC01 and VRC02 antibodies not only attach to the CD4 binding site but are currently the most potent antibodies known to scientists, deactivating over 90% of circulating variants.
“The antibodies attach to a virtually unchanging part of the virus, and this explains why they can neutralize such an extraordinary range of HIV strains,” says John R. Mascola, M.D., the deputy director of the VRC.
Interestingly, the researchers have also pinpointed the anatomic structure of the antibody VRC01 as it attaches to the HIV virus. This discovery provides scientists the information needed to begin developing synthetic compounds that will elicit the body’s ability to produce these neutralizing antibodies.
The Bottom Line
This is clearly an exciting breakthrough in the worldwide fight against AIDS. These newly identified, naturally occurring antibodies certainly help to shed more light on the mystery of the HIV virus.
“In addition,” as Dr. Anthony S. Fauci, director of NIAID, points out, “the technique the teams used to find the new antibodies represents a novel strategy that could be applied to vaccine design for many other infectious diseases.”