Many thousands of people around the world die of typhoid fever every year, but little is known about how the bacterium Salmonella enterica Typhi causes the disease. A protein identified on the microbe's outer surface seems to be key to S. enterica Typhi's virulence and could be a target for more effective vaccines.

Using bioinformatic techniques, Santasabuj Das and his colleagues at the National Institute of Cholera and Enteric Diseases in Kolkata, India, looked for S. enterica Typhi proteins that could bind to host receptors and homed in on one, called T2544. Bacteria in which the gene for this protein had been deleted showed reduced adhesion to human cells and, in particular, to laminin, a protein abundant in the matrix between cells. When mice were infected with a specific dose of the normal bacteria, half died within a week, whereas animals infected with the same dose of the mutant strain all survived. Moreover, T2544 triggered a protective antibody response in the mice.

Proc. Natl Acad. Sci. USA doi:10.1073/pnas.1016180108 (2011)