Non-IgA fc binding forms of the Group B streptococcal beta antigens

A mutant Cβ protein comprising the amino acid sequence A-X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12-B, wherein A comprises amino acids 1-164 of the sequence shown in FIG. 1 (SEQ ID NO:

• 2), B represents a sequence starting from amino acid 177 and terminating at an amino acid between residue 1094 and 1127, inclusive, of the sequence shown in FIG. 1 (SEQ ID NO:
• 2), and X1-X12 are each selected independently from the group consisting of Ala, Val, Leu, Ile, Pro, Met, Phe, Trp, a bond, and the wild type amino acid found at the corresponding position of the sequence shown in FIG. 1 (SEQ ID NO:
• 2), wherein said amino acid positions are numbered from the first amino acid of the native amino acid sequence encoding said protein, with the proviso that at least one of X1 through X12, inclusive, is other than the wild type amino acid, and wherein the LPXTG motif may be missing from the mutant Cβ protein.

A method of inducing an immune response in a mammal, comprising administering a vaccine comprising at least one mutant Cβ protein comprising the amino acid sequence A-X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12-B, wherein A comprises amino acids 1-164 of the sequence shown in FIG. 1 (SEQ ID NO:

• 2), B represents a sequence starting from amino acid 177 and terminating at an amino acid between residue 1094 and 1127, inclusive, of the sequence shown in FIG. 1 (SEQ ID NO:
• 2), and X1-X12 are each selected independently from the group consisting of Ala, Val, Leu, Ile, Pro, Met, Phe, Trp, a bond, and the wild type amino acid found at the corresponding position of the sequence shown in FIG. 1 (SEQ ID NO:
• 2), wherein said amino acid positions are numbered from the first amino acid of the native amino acid sequence encoding said protein, with the proviso that at least one of X1 through X12, inclusive, is other than the wild type amino acid, and wherein the LPXTG motif may be missing from the mutant Cβ protein, together with a pharmaceutically acceptable carrier, in an amount sufficient to induce an immune response in a mammal.