Mutant antigen may improve meningitis vaccine development

A study conducted by the University of Massachusetts Medical Center and the Children’s Hospital & Research Center Oakland has identified a new mutant vaccine antigen that may improve the development of an effective meningitis vaccine.  

Meningococci are the bacteria that cause meningitis and other severe infections of the bloodstream. These infections are dangerous to children and teenagers. Around 10 percent of the infected may not survive while 20 percent are left with long-term medical problems.

There are vaccines against certain strains of the bacteria, but there are no “group B” vaccines, which account for 40 percent of all U.S. cases. Two vaccines are currently in development using a novel antigen called factor H-binding protein.

During an experiment with mice genetically engineered to have a more human factor H, the original antigen had trouble protecting the mice from meningitis. By using an fHbp antigen that had a slight mutation, there was a significant increase in protection.

“This mutant antigen has just one amino acid different between it and the fHbp in the current vaccines, but that difference means that it no longer binds to human fH, and that resulted in much higher protective responses,” Dr. Dan Granoff, director of CHORI’s Center for Immunology and Vaccine Development said. “It’s really quite gratifying to have a study like this that has direct translation into making better vaccines against infections, especial meningococcal disease.”

The study also lends credence to the principle that vaccines that do not directly target fH binding proteins may provide stronger protection, such as in other bacterial diseases like pneumococcus and Bordatella.