Potential of protein OprF of Pseudomonas in bivalent vaccines.

Outer membrane protein OprF is the major outer membrane of Pseudomonas aeruginosa, and has been expressed to a similar high level in Escherichia coli from the cloned gene. It contains conserved surface epitopes, and antibodies against these epitopes can protect mice from P. aeruginosa infections. To develop the oprF gene as a carrier for foreign epitopes, linker insertion mutagenesis has been performed to introduce 12 nucleotide inserts marked by a unique PstI site. Nine such sites can accept and express a foreign epitope within the surface loop regions of OprF on the surface of E. coli. The antigenicity at a given insertion site, and the influence of the length of a model repeating malarial epitope on antigenicity, have been shown to be site-specific and apparently dependent on the nature of the surrounding amino acids at the insertion site. Immunization of mice with OprF containing a highly antigenic inserted epitope led to an epitope-specific antibody response. These data suggest that OprF has potential for use as a carrier for foreign epitopes.