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For the design of potent subunit vaccines, it is of paramount importance to identify all antigens immunologically recognized by a patient population infected with a pathogen. We have developed a rapid and efficient procedure to identify such commonly recognized antigens, and here we provide a comprehensive in vivo antigenic profile of Staphylococcus aureus, an important human pathogen. S. aureus peptides were displayed on the surface of Escherichia coli via fusion to one of two outer membrane proteins (Lamb and FhuA) and probed with sera selected for high Ab titer and opsonic activity. A total of 60 antigenic proteins were identified, most of which are located or predicted to be located on the surface of the bacterium or secreted. The identification of these antigens and their reactivity with individual sera from patients and healthy individuals greatly facilitate the selection of promising vaccine candidates for further evaluation. This approach, which makes use of whole genome sequence information, has the potential to greatly accelerate and facilitate the formulation of novel vaccines and is applicable to any pathogen that induces Abs in humans and/or experimental animals.

Research reveals that Yersinia cells adhering to animal cells deliver a cocktail of effector Yops molecules through a type III secretion-translocation system. Data indicate that the binding domain residues of SycE mediate transfer into the target cells.

The Yersinia outer membrane protein (YOP) and the type III virulence system of the pathogenic bacteria were described. This system involved the transfer of bacterial proteins by the extracellular bacteria to the cytosol of the eukaryotic cell. The three species of Yersinia considered as pathogens in mammals are Y. pestis, Y. pseudotuberculosis and Y. enterocolitica. Genetic analysis revealed that majority of Yop proteins were necessary for virulence and cytotoxicity activity. The Yops were classified as secreted proteins. The pYV plasmid and the ysc genes encoded the Yop secretion apparatus.