Abstract: The present invention pertains to a composition for the manufacture of a medicament comprising living or dead bacteria with controlled amounts of surface-coupled proteins or proteinaceous compounds and a method for the preparation of the composition. The bacterium provides a multivalent heterologous protein display vehicle that may be used in the manufacture of vaccines or medicaments for delivery via the mucosa.

Abstract: Nucleotide sequences coding for a promoter activity-regulating polypeptide designated OrfY, isolated from Lactococcus lactis, and promoter activity-regulating active homologues and fragments hereof is used to indirectly regulating the expression of genes. The coding sequence is inserted into lactic acid bacterial cells or any other cells with the objective of either reducing or enhancing the expression level of the gene being under the control of the promoter sequence, the activity of which is regulated by the OrfY polypeptide or homologues or fragments hereof. Improved gene expression systems are provided based on this promoter activity-regulating polypeptide.