CELL-SURFACE DISPLAY OF HETEROLOGOUS EPITOPES ON STAPHYLOCOCCUS-XYLOSUS AS A POTENTIAL DELIVERY SYSTEM FOR ORAL VACCINATION

A system has been developed for the surface expression of heterologous receptors on the cell surface of Staphylococcus xylosus. Gene fragmen ts encoding peptides to be displayed on the cell surface can be assemb led by applying a polymerization strategy based on the class-IIS restr iction enzyme BspMI and thereafter subcloned into an Escherichia coli- staphylococci shuttle vector designed for targeting of produced fusion proteins to the outer cell surface of the Gram-positive host cell. A heterologous receptor was genetically assembled and expressed on the s urface of S. xylosus where the separate regions could be independently probed in immunogold assays, using rabbit antisera reacting with diff erent regions of the recombinant receptor. In addition, a receptor-spe cific humoral immune response could be elicited in mice by oral immuni zation with recombinant S. xylosus cells, suggesting that these type o f Gram-positive bacteria might offer potential vehicles for oral vacci nation.