Important step made towards salmonella vaccine

The research team has identified a set of antigens — molecules in the invading bacteria that trigger an immune response — that is common to both mice and humans.

 

“These antigens will provide the research community with a foundation for developing a protective salmonella vaccine,” said Stephen McSorley, an immunologist and associate professor in the UC Davis Center for Comparative Medicine, which investigates diseases that afflict both humans and animals.

 

There are currently no vaccines for the strains of salmonella that cause these type of illnesses. Furthermore, salmonella bacteria increasingly are becoming resistant to existing antibiotic treatments. And no new, effective antibiotics are on the horizon.

 

In an effort to identify those antigens, the research team created an array, or collection, of 2,700 proteins, representing approximately 60 percent of all proteins produced by salmonella bacteria. The researchers found that 117 of those proteins behaved as antigens when mixed with blood serum from salmonella-infected mice, triggering an immune response to defend against the bacterial infection. Fourteen of those proteins were common to all four strains of mice involved in the study.

The researchers also identified 14 proteins that served as antigens in the blood serum from Malawian children infected with salmonella. Eight of those 14 proteins, or 57%, were among the 117 antigens identified in the mice.

 

“Discovery of the eight antigens in both mouse and human infections suggests that some of these antigens might be successfully used in developing a vaccine to protect against salmonella and that the mouse model of salmonella will be useful before vaccine research moves into clinical trials,” McSorley said.

 

Also collaborating on this project: UC Irvine; the University of Malawi, Chichiri, Malawi; Novartis Vaccines Institute for Global Health, Sienna, Italy; and the University of Birmingham, England.
The researchers’ discovery will be published in the early edition of the Proceedings of the National Academy of Sciences.