By DR. TIFFANY CHAO, ABC News Medical Unit

We might not have a cure for the common cold, but scientists have discovered a potentially powerful new treatment for much more dangerous flu viruses.

Researchers at Scripps Research Institute in La Jolla, Calif., and Crucell Vaccine Institute in the Netherlands say they have discovered a human antibody that protects against essentially all influenza A and B strains.

The researchers believe the antibody could be used to offer something that has never been available before - an actual treatment for patients who are infected with the flu. Currently, such patients are only given supportive treatment while their bodies fight off the infection on their own.

The discovery may even pave the way to a universal flu vaccine, effective against nearly all flu strains, that could be delivered in a one-time shot similar to immunization against diseases like chickenpox and measles.

Ideally, such a vaccine would eliminate the need for annual flu shots, which are specifically tailored to seasonal strains.

Their report appeared Thursday in the journal Science.

In order to find the antibody, the researcher first vaccinated a number of human volunteers. They took the antibodies generated in the bodies of these subjects and injected them into mice. What they found was that one of the antibodies protected mice from the major influenza A and B viruses - including the dreaded H1N1 subtype.

"To develop a truly universal flu vaccine or therapy, one needs to be able to provide protection against influenza A and influenza B viruses," said Ian A. Wilson, Hansen professor of structural biology at Scripps Research and the new study's senior investigator. "With this report, we now have broadly neutralizing antibodies against both."

In other words, this finding may portend a universal treatment for nearly all strains of the flu.

"The Holy Grail of influenza research is to find a mechanism to protect people against essentially all the numerous different strains of influenza viruses," said Dr. William Schaffner, professor and chair of preventive medicine at Vanderbilt University. "This research is a heartening step forward."

Also heartening is the concept that this antibody could be used to help unvaccinated people who are already sick with the flu. As in the mouse models, patients could receive an antibody-based treatment, similar to existing treatments for people who are exposed to tetanus, rabies and hepatitis B.

"If this is true, it is big news in that it allows us to protect those too young or old to benefit from flu vaccines, and those immunocompromised from a large variety of illnesses that don't allow them to respond to vaccines," said Dr. Gregory A. Poland, a professor of medicine, infectious diseases, molecular pharmacology and experimental therapeutics at the Mayo Clinic and Foundation.

This would include those affected by the dangerous H1N1 and other subtypes of influenzas.

Poland said that if the results pan out, the antibody could be "a critical component of our armamentarium" against mutant and pandemic flu strains for which there are currently no vaccines - including the H3N2v variant that the CDC addressed in a Thursday teleconference.

Poland added that he is hopeful that the finding could also point the way toward generating a universal flu vaccine.

"Understanding the structure of these antibodies could allow us to engineer and design vaccines that produce these same antibodies in the human body and, thereby, protect against influenza," he said. "More importantly, it could allow development of so-called 'universal' flu vaccines that would protect against all flu strains."

Of course, while the potential for this antibody is great, Vanderbilt's Schaffner cautioned that further research needs to be done in humans.

"Sometimes what seems to work in mice in the laboratory does not perform as well in humans who are out in the world," he said. "Nevertheless, the investigators have earned congratulations and this finding opens the door."