Two scientists in Tennessee received Food and Drug Administration approval Friday to test a vaccine to prevent acquired immune deficiency syndrome.
Short of a cure, one of the golden rings in the 16-year global AIDS pandemic has been to produce an effective vaccine for healthy people, something akin to being immunized for polio or measles.
The trouble has been HIV’s rapid mutation rate - the mind-boggling speed at which the virus continues to reinvent itself. A vaccine based on a virus one year is useless the next.
Worse still, there are numerous strains of HIV.
Julia Hurwitz and Karen Slobod of St. Jude Children’s Research Hospital in Memphis have come up with a vaccine they think will be effective against a virus with multiple lethal personalities.
They’ve taken the outer protein coats - the envelopes that enfold 23 AIDS viral strains - and incorporated them into their new vaccine.
“The idea is that if people get infected with any one of these viruses, they will have protection,” Hurwitz, a molecular biologist, said.
“When you look at the sequence of amino acids in the envelope,” Hurwitz said of the myriad string-of-pearls fragments that make up a protein, “you’re really looking at a lot of different shapes.”
In short, some coat proteins will curl their string of pearls into a circle, others will shift shapes into squares or triangles. “That’s what the immune system sees, the shape.” So their hypothesis is that once the body has recognized these various coat proteins, it will produce antibodies against them.
“What is novel about this is the approach they’ve tried, to answer the question about the genetic variation of the AIDS virus,” said Dr. Mark Grabowsky, chief of the clinical development branch at the National Institute of Allergy and Infectious Diseases in Bethesda, Md., which oversees vaccine development.
Grabowsky said a number of teams have developed vaccines - there have been 43 government-sponsored trials of candidate vaccines since 1988 - but none has been based on two dozen coat proteins.
“We have sample viruses from around the world,” Hurwitz said.
Protein coats from these viruses are not infectious and so pose no risk to the volunteers.
Slobod, a medical doctor who will conduct the clinical side of the test, is seeking nine to 18 healthy volunteers to be injected with the HIV vaccine.