For the first time, researchers have been able to create an HIV vaccine capable of neutralizing multiple strains of the virus in animals, according to a study published online March 11 in the Journal of Virology and reported by ScienceDaily. The authors caution that this is just a first step toward creating an effective vaccine for humans, but a big step nonetheless.

A major obstacle facing HIV vaccine development is the ease with which the virus mutates. Certain vaccines can make a person’s immune system produce antibodies to specific parts of the virus, but these antibodies are greatly limited because HIV quickly evolves to evade them.

Gail Ferstandig Arnold, PhD, and Eddy Arnold, PhD—a married couple who work together at the Department of Chemistry and Chemical Biology at Rutgers University in Piscataway, New Jersey—report that they have created a vaccine candidate that can neutralize many strains of the virus. They accomplished this by first creating a library of millions of viral proteins and honing in on the ones absolutely essential for viral reproduction. If HIV were to try to mutate away from using these proteins in their current configuration, the resulting viruses would be less able to reproduce.

The Arnolds attached their protein cluster to the surface of the common cold virus, a rhinovirus, and tested it in guinea pigs. The guinea pigs were able to make antibodies that in test tubes neutralized a broad variety of strains of HIV. This is the first time that scientists have been able to make a vaccine capable of producing broadly neutralizing antibodies.

“We need to be careful to not overstate things because the quantity of response is not huge, but it is significant,” Eddy Arnold said. “It is probably not potent enough by itself to be the vaccine or a vaccine, but it is a proof of principle that what we are trying to do is a very sound idea.”