Stabilisation of plasmid inheritance in bacteria

摘要

The invention relates to a vaccine comprising a pharmaceutically acceptable carrier or diluent and a bacterium, wherein the bacterium contains (i) a DNA sequence encoding a site-specific recombinase, and (ii) a plasmid comprising a recognition element for the recombinase and a DNA sequence encoding a heterologous polypeptide. The recombinase stabilises inheritance of the plasmid and thereby prevents the bacterium from losing the ability to express the heterologous polypeptide.