New Cholera Vaccine and Method for Conjugating Bacterial Polysaccharides to Proteins

A new conjugate vaccine for cholera has been developed. The invention includes a new method to conjugate the O-specific polysaccharide-core part of the bacterial lipopolysaccharide and protein subcomponents. Conventional technology has entailed chemical treatment of both components to introduce linkers, which made them amenable for covalent linking. The new method simplifies production by utilizing squaric acid chemistry for conjugating the free amine-containing species (e.g. polysaccharides) directly to amine-containing species (e.g. proteins) without prior modification of either component. While demonstrated in this new cholera prototype vaccine, the technology is envisioned as generally applicable, thereby streamlining a complex production process.

Potential Commercial Applications: Competitive Advantages:
  • Simplified production of conjugate vaccines
  • New vaccines
  • The method in the present form is simple to perform, gives reproducible results, allows preparation of carbohydrate-protein constructs in a predictable way, and appears to be superior to protocols developed earlier.

Development Stage:


Pavol Kovac (NIDDK)  ➽ more inventions...

Peng Xu (NIDDK)  ➽ more inventions...

Mohammed Alam

Anuj Kalsy

Richelle Charles

Stephen Calderwood

Dwight Peterson (FDA)  ➽ more inventions...

Edward Ryan

Firdausi Qadri

Willie Vann (FDA)  ➽ more inventions...

Intellectual Property:
US Pat: 9,616,139 issued 2017-04-11
US Application No. 61/569,632 filed on 2011-12-12
PCT Application No. PCT/US12/046196 filed on 2012-07-11
US Application No. 14/128,958 filed on 2014-09-08

Peng Xu, et al. PMID 21899371

Collaboration Opportunity:

The National Institute of Diabetes and Digestive and Kidney Diseases is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate or commercialize conjugate vaccines. For collaboration opportunities, please contact Marguerite J. Miller, M.B.A. at 301-496-9003 or

Licensing Contact:
Carolyn Buller,
Phone: 301-443-5605

OTT Reference No: E-234-2011-0
Updated: Jul 12, 2017