Genetically engineered bacteria may improve vaccine efficacy

Sixty-one new strains of genetically engineered bacteria have been developed by researchers at the University of Texas at Austin to improve the efficacy of vaccines for such diseases as flu, pertussis, cholera and HPV.

The new E. coli strains are part of a new class of biological adjuvants that some believe could transform vaccine design.

"For 70 years the only adjuvants being used were aluminum salts," Stephen Trent, an associate professor of biology in the College of Natural Sciences, said. "They worked, but we didn't fully understand why, and there were limitations. Then four years ago the first biological adjuvant was approved by the Food and Drug Administration. I think what we're doing is a step forward from that. It's going to allow us to design vaccines in a much more intentional way."

The engineered E. coli bacteria express endotoxins in multiple configurations on its surface. Endotoxin molecules, which can be dangerous, exist on the cell surface of many types of bacteria. Because of that, humans have evolved the ability to detect and respond to them quickly.

"These 61 E. coli strains each have a different profile on their surface," Brittany Needham, a doctoral student in Trent's lab and the first author on the paper, said. "In every case the surface structure of the endotoxin is safe, but it will interact with the immune system in a range of ways. Suddenly we have a huge potential menu of adjuvants to test out with different kinds of vaccines."