Shigellosis is a global human health problem. Transmission usually occurs by contaminated food and water, or through person-to-person contact. The bacterium is highly infectious by the oral route, and ingestion of as few as 10 organisms can cause an infection in volunteers. An estimated 200 million people worldwide suffer from shigellosis, with more than 650,000 associated deaths annually. The CDC recently estimated the occurrence of over 440,000 annual shigellosis cases in the United States alone, approximately eighty percent (80%) of which are caused by Shigella sonnei. Shigella sonnei is more active in developed countries. Shigella infections are typically treated with a course of antibiotics. However, due to the emergence of multidrug resistant Shigella strains, a safe and effective vaccine is highly desirable. No vaccines against Shigella infection currently exist. Immunity to Shigellae is mediated largely by immune responses directed against the serotype specific Opolysaccharide.
FDA inventors developed compositions and methods for inducing an immunoprotective response against S. sonnei. Specifically, an attenuated bacteria capable of expressing an S. sonnei antigen comprised of the S. sonnei form I O-polysaccharide expressed from the S. sonnei rfb/rfc gene cluster is claimed. The inventors have demonstrated the candidate vaccine compositions provide one hundred percent (100%) protection against parenteral challenge with virulent S. sonnei in mice.
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Inventors: Dennis Kopecko, De Qi Xu, John Cisar
- Kopecko, D et al., Molecular cloning and characterization of genes for Shigella sonnei form I O polysaccharide: proposed biosynthetic pathway and stable expression in a live salmonella vaccine vector. Infect Immun. 2002 Aug;70(8):4414-23. PMID:12117952
United States Patent: US 7,541,043 B2 issued 06.02.2009
United States Patent: US 8,071,084 B2 issued 06.12.2011
United States Patent: US 8,337,832 B2 issued 12.25.2012
United States Patent: US 8,992,943 B2 issued 03.31.2015
United States Patent: US 9,333,251 B2 issued 05.10.2016
Product Area: Shigella Vaccine, Shigella therapeutic, Shigella diagnostic
FDA Reference No: E-2001-016
Ken Millburne, J.D.
FDA Technology Transfer Program