A New Look at the Enterobacterial Common Antigen Forms Obtained during Rough Lipopolysaccharides Purification.

Enterobacterial common antigen (ECA) is a conserved antigen expressed by enterobacteria. It is built by trisaccharide repeating units: →3)-α-D-Fuc4NAc-(1→4)-β-D-ManNAcA-(1→4)-α-D-GlcNAc-(1→ and occurs in three forms: as surface-bound linear polysaccharides linked to a phosphoglyceride (ECA) or lipopolysaccharide - endotoxin (ECA), and cyclic form (ECA). ECA maintains, outer membrane integrity, immunogenicity, and viability of enterobacteria.