Advances in new vaccines against human enterotoxigenic Escherichia coli-A review

Abstract:

Enterotoxigenic Escherichia coli (ETEC) is the most common cause of diarrhea, which is a second leading cause of death for the children under five years old from all over the world. The key factors of ETEC contain both colonization factors (CFs) and enterotoxins including heat-labile enterotoxin (LT) and heat-stable enterotoxin (ST). CFs mediated the binding of bacteria to the host intestinal epithelial cells, whereas LT and ST stimulated the over-secretion of body fluids and electrolytes, resulting in the destruction of the host fluid balance and leading diarrhea. The vaccine against CFs and enterotoxins could stimulate the host immune response, blocking ETEC adhesion and neutralizing enterotoxins, which is effective in the prevention of ETEC diarrhea. For the moment, depending on the stimulated immune response against LT, a cholera vaccine called Dukoral ® has been approved for use in some countries for the short-term protection and prevention of travelers' diarrhea. ETEC candidate vaccines are still in progress, which is designed to provide a long and wide-spectrum protection for ETEC infections. This paper briefly summarizes the advanced findings and key problems of vaccine development, and discusses prospects for future research.