UC-Davis uncovers possible foundation for Salmonella vaccine

DAVIS, CALIF. — An international research team led by Stephen McSorley, an immunologist and associate professor in the University of California-Davis (UC-Davis) Center for Comparative Medicine and the School of Veterinary Medicine, identified a set of antigens that could provide a foundation for developing a protective Salmonella vaccine.

In an effort to identify the antigens, the research team created a 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, according to UC-Davis. 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 percent, 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 says.

More than 1.4 million cases of Salmonella are reported annually in the United States, costing an estimated $3 billion and causing more than 500 deaths. There are currently no vaccines for the strains of Salmonella that cause these types of illnesses, and UC-Davis says Salmonella is becoming increasingly resistant to antibiotics.

Other collaborators on the study include the UC-Irvine, the University of Malawi, Novartis Vaccines Institute for Global Health and the University of Birmingham in England.The National Institutes of Health, the Wellcome Trust and GlaxoSmithKline provided funding for the study.

The study was published Feb. 13 in the Proceedings of the National Academy of Sciences (PNAS).