| CPC A61K 39/0283 (2013.01) [A61K 39/0275 (2013.01); A61K 39/116 (2013.01); A61K 2039/522 (2013.01); A61K 2039/523 (2013.01); A61K 2039/543 (2013.01); A61K 2039/70 (2013.01); Y02A 50/30 (2018.01)] | 11 Claims |
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1. A method of treating or reducing the incidence of shigellosis in a human subject comprising oral administration of one or more doses of a vaccine, said vaccine comprising a transgenic Ty21a Salmonella typhi Ty21a, which comprises (i) a heterologous Shigella sonnei O-antigen biosynthetic gene region comprising a wzz gene, wherein the wzz gene comprises a DNA sequence that shares at least 95% sequence identity with the DNA sequence of nucleic acids 4,511,904 to 4,513,010 of SEQ ID NO: 4; and (ii) a heterologous acid resistance biosynthetic gene system comprising one or more YbaS genes; wherein said heterologous Shigella sonnei O-antigen biosynthetic gene region and said heterologous acid resistance biosynthetic gene system are both integrated into the Salmonella typhi Ty21a chromosome, and wherein:
a. the heterologous Shigella sonnei O-antigen is stably expressed;
b. the one or more YbaS genes are stably expressed;
c. said transgenic Salmonella typhi Ty21a is more acid stable at pH 2.5 than Salmonella typhi Ty21a without the integrated acid resistance biosynthetic gene system;
d. an immune response is elicited against virulent Shigella sonnei challenge; and,
e. an immune response is elicited against virulent Salmonella typhi challenge.
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