Using E. coli to transport next-gen vaccines


University of Buffalo

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Another day, another recall: One of the latest is flour. On May 31, says the Centers for Disease Control and Prevention (CDC), General Mills recalled several sizes and varieties of Gold Medal Flour, Gold Medal Wondra Flour and Signature Kitchens Flour due to possible E. coli contamination. On July 1, the company expanded the recall to include additional lots of flour sold under the same brand names. The recalled flours, listed here, were sold nationwide.

Quite naturally, the notion of ingesting something contaminated with E. coli is far from appetizing.

But what if the headline-grabbing bacteria could be used to fight disease?

As it turns out, only certain strains of E. coli are harmful to us. Harmless strains of the bacteria are not only safe but also essential to healthy human digestion. Using these harmless strains, researchers have developed an E. coli-based transport capsule designed to help next-generation vaccines do a more efficient and effective job than today's immunizations.

The research, described in a study published in the journal Science Advances, highlights the capsule's success fighting pneumococcal disease, an infection that can result in pneumonia, sepsis, ear infections and meningitis.

"It's a bit counterintuitive given what you hear about E. coli, but there are many strains of the bacteria, most of which are perfectly normal in the body that have great potential to fight disease," said Blaine A. Pfeifer, PhD, associate professor of chemical and biological engineering in the University at Buffalo School of Engineering and Applied Sciences.

Pfeifer is the study's co-lead author along with his former student Charles H. Jones, PhD, who is leading efforts to commercialize the biotechnology as CEO and founder of Buffalo, New York-based startup Abcombi Biosciences.

The core of the capsule is harmless E. coli. Around the bacteria, the researchers wrapped a synthetic polymer — called poly (beta amino ester) — like a chain link fence. The positive-charged polymer, combined with the negative-charged bacteria cell wall, create a sort of hybrid capsule.

To test the capsule, the researchers then inserted a protein-based vaccine, also being commercialized by Abcombi, designed to fight pneumococcal disease. The results, when tested in mice, were impressive, they say.

The capsule's hybrid design provided:

  • Both passive and active targeting of specific immune cells called antigen-presenting cells that trigger an immune response.
  • Natural and multi-component adjuvant properties, which enhance the body's immune response.
  • Dual intracellular delivery mechanisms to direct a particular immune response.
  • Simultaneous production and delivery of the components (antigens) required for a vaccine.
  • Strong vaccination protection capabilities against pneumococcal disease.

It's also relatively inexpensive to create and flexible in terms of use. The capsule could, for example, be used as a delivery device for therapies that target cancer, viral-based infectious disease and other illnesses.