Abstract: Tripartite recombinant DNA encoding fusion proteins which comprise three sequences, i.e., a signal peptide which is operable in a Gram positive bacterium, an immunogenic polypeptide linked thereto which is not normally expressed in a Gram positive bacterium, and a cell wall spanning and a membrane anchoring sequence, as well as their use in Gram positive bacteria to express the resultant fusion protein on their surface are described. The preferred cell wall spanning and anchoring polypeptides include Staphylococcus protein A and Streptococcus protein G.

Abstract: Novel proteins obtainable by mutagenesis of surface-exposed amino acids of domains of natural bacterial receptors, said proteins being obtained without substantial loss of basic structure and stability of said natural bacterial receptors; proteins which have been selected from a protein library embodying a repertoire of said novel proteins; and methods for the manufacture of artificial bacterial receptor structures.