Edible vaccine to combat E coli

Scientists announced this week that they are developing an edible vaccine that could stop the E. coli bacteria where it starts - in cattle and other livestock, ReutersHealth reports. The most efficient way to deliver such a vaccine would be to add it to the animals' feed, explained researcher Nicole Roup, a graduate student at the Uniformed Services University of the Health Sciences in Bethesda, Maryland. ``We're looking specifically at corn,''​ Roup said. She presented her findings on Tuesday at the annual meeting of the American Society for Microbiology, Orlando, US. The E. coli 0157:H7 strain is the most common cause of infectious bloody diarrhea in the United States, linked to nearly 73,000 cases every year. Because cattle are a main reservoir for E. coli, it made sense to try to combat the problem there, Roup told Reuters Health. Previous research had demonstrated that plants make cheap, safe vehicles for the transmission of vaccines, so Roup looked to find a suitable E. coli vaccine for introduction into plant cells. She selected a a protein called intimin, found on the outer coat of the E. coli organism. Intimin ``helps the bacteria adhere to the intestinal surface,''​ Roup explained. Priming the cattle's immune system to recognise intimin could serve as a potent vaccine to reducing E. coli infection rates, Roup theorised. Her studies in tobacco plant cells showed that plants can be genetically engineered to carry genes expressing intimin. And in experiments in mice, animals fed genetically-altered plant cells displayed an ``intimin-specific immune antibody response,''​ Roup said.The next step is to test the vaccine in cattle feed. Source: ReutersHealth​