Enterobacterial Antigen Analogs Synthesized

In an advance that could lead to new treatments for bacterial infections, researchers have synthesized oligosaccharides that stimulate the immune system to generate antibodies against enterobacteria, such as Salmonella,Klebsiella, and Escherichia coli. Many strains of these pathogenic bacteria have developed resistance to conventional antibiotics. Some scientists think vaccines that elicit bacteria-specific antibodies might be a solution to that problem. One promising antigen for such vaccines is enterobacterial common antigen (ECA), an oligosaccharide found on the surfaces of all enterobacteria. The antigen can be isolated from natural sources, but chemical synthesis would provide practical amounts for immunotherapy studies. Qun Wang of the biologic drug firm MedImmune, Geert-Jan Boons of the University of Georgia, and coworkers synthesized variants of the oligosaccharide ECA that can be easily conjugated with carrier proteins to trigger a response from the immune system (Angew. Chem. Int. Ed. 2015, DOI: 10.1002/anie.201505420). The researchers used the antigen conjugates to develop a monoclonal antibody that recognizes ECA on various enterobacteria. They’re now studying the antibody’s therapeutic potential.