Abstract: Modified bacterial surface layer (S-layer) proteins are disclosed where the modification is the insertion, at an internal location, of a heterologous polypeptide, or polypeptide of interest. The polypeptide is a binding or target protein, such as an antigen or antibody, or part thereof, in particular a bacterial antigen (e.g. from Clostridium tetani such as TTFC). The modified surface layer protein can then be expressed on the surface of the bacterial cell and used in a vaccine. Also disclosed are bacteria which have been modified to express a heterologous surface layer protein, but which do not as a wild-type possess an S-layer (such as L. casei), and modified bacteria which express only a modified surface layer protein (and not the wild-type S-layer protein). The wild type S-layer is completely replaced with the modified version where the polynucleotide encoding the modified version is integrated into the bacterial genome.

Abstract: Modified bacterial surface layer (S-layer) proteins are disclosed where the modification is the insertion, at an internal location, of a heterologous polypeptide, or polypeptide of interest. The polypeptide is a binding or target protein, such as an antigen or antibody, or part thereof, in particular a bacterial antigen (e.g. from Clostridium tetani such as TTFC). The modified surface layer protein can then be expressed on the surface of the bacterial cell and used in a vaccine. Also disclosed are bacteria which have been modified to express a heterologous surface layer protein, but which do not as a wild-type possess an S-layer (such as L. casei), and modified bacteria which express only a modified surface layer protein (and not the wild-type S-layer protein). The wild type S-layer is completely replaced with the modified version where the polynucleotide encoding the modified version is integrated into the bacterial genome.