Protein Rallies Immune System Against Flu

Researchers have found that a synthetic protein, called EP67, instructs the body to respond against disease-causing organisms

A synthetic protein given shortly after exposure to the flu bug might keep you from getting sick. The protein acts by rallying the immune system against the invading virus more quickly than usual.

Researchers began taking a closer look at the man-made protein, called EP67, in 2004, after discovering that when combined with vaccines, it helped increase the body’s immune response against a variety of disease-causing microorganisms.  

Biologist Joy Phillips and colleagues at San Diego State University in California then wondered whether EP67 alone would boost the immune system.

In experiments with a strain of influenza A virus that infects mammals, including humans, Phillips narrowed down EP67’s mechanism. She says the protein doesn’t attack the virus. Instead, it stimulates the body's immune system, which acts as a sentry and instructs the body to produce specific immune responses against the disease-causing organism.

“It basically tells the immune system, ‘Look out. There’s a giant problem right here. You need to send in help,’” Phillips says.

Phillips led a team of researchers that infected mice with influenza A.  Rodents that received a dose of EP67 within 24 hours of exposure to the pathogen did not get nearly as sick as mice that were not treated with the protein.

The rodent's level of illness was measured by weight loss. The untreated mice lost 20 percent of their body weight and some of them died, compared to the other mice that lost only six percent of their weight. Most importantly, treated mice given a normally lethal dose of influenza survived.

Phillips says the results suggest that - if given within a day of exposure - EP67 can be effective against virtually any strain of virus, bacteria, or fungus and even some pathogens that haven’t yet been identified. The flu vaccine, for example, must exactly match the currently circulating strain in order to work.

“It’s designed to respond against everything," Phillips says, "and to save your life until your very specific immune system can come up and clean up the final parts of the threat.”

But there may be one virus EP67 can’t protect against - HIV. The problem, according to Phillips, is that the virus that causes AIDS cripples the body's immune system by infecting its most important components, the T cells. That is one of the reasons it has been so difficult for scientists to develop an effective vaccine against HIV.