A new study from researchers at UPMC and the University of Pittsburgh may be a first step in creating vaccines that protect people against a wider range of bacteria.
According to the research of Pitt professor Dr. Jay Kolls and his colleagues, vaccines to prepare "T" cells for infection rather than "B" cells might give people more bang for their buck.
Current vaccine methods target B cells, in order to have those cells create antibodies that would help the body ward off one specific bacterium if it's encountered. Each type of antibody matches up with a specific sugar complex of the bacterium's "coat" or capsule. The antibodies attach to the invading bacteria cells and ""tag" them for destruction by other cells.
If vaccines targeted T cells instead, one type of T cell (Th17) could learn to respond to bacteria in a way similar to antibodies. The difference is that the Th17 cells can recognize and respond to the protein complexes of cell membranes, rather than the sugar complexes of cell capsules.
It may not sound like much of a difference, but since many different types of bacteria share the same protein complex, the body would be prepared for many types of bacteria with only one vaccination. To Kolls and his team, that's preferable to a series of shots to defend against just one type of bacterium.
"For example, you could get a pneumonia shot at the doctor's office now. They mix different sugars from the wall of the bacteria to try to cover the most common [strains]," said Kolls. "What we showed was that in addition to these sugar epitopes that activate B cells, you could essentially take these proteins and use them as vaccines, [and] they may have some advantage for drug-resistant organisms or organisms with a lot of different sugars."
The study was performed on mice, but Kolls said that he's looking forward to several applications for humans, including providing protection against many strains of Streptococcus pneumoniae.
"That's the pneumonia vaccine that you currently get at the doctor's office now, and that's still a common cause of pneumonia, sinus infection, middle ear infection, and, in the most severe form, of meningitis," said Kolls. "The infections that are being caused now by this bug sometimes can be caused by strains that aren't covered in current vaccines."
The research team includes scientists not only from Pitt and UPMC, but also from Louisiana State University, the University of Alabama, and the University of Queensland in Brisbane, Australia. The team's report was published on December 22 in the online journal Immunity.
