A multi-institutional team has added more than 20 pathogens to the list of known bacteria that express poly-N-acetylglucosamine, a bacterial capsule polysaccharide that provides a potentially broad-spectrum target for vaccination.1 The findings open up new indications for Alopexx Vaccine LLC and Alopexx Pharmaceuticals LLC, which are already developing a vaccine and an antibody for passive immunization, respectively.
Over the past two decades, studies by multiple groups have identified poly-N-acetylglucosamine (PNAG), a polysaccharide encoded by a conserved four-gene locus, as a component of the surface capsule in at least seven species of bacteria.2-7
PNAG is one of many polysaccharides and other carbohydrate polymers found on the outer surface of bacteria that help prevent host macrophages and other cells from engulfing the pathogens.
Anti-PNAG antibodies have been found in circulation in humans and other animals, but these naturally occurring antibodies do not effectively kill PNAG-expressing bacteria or provide adequate immune protection against them, casting doubts on their prophylactic potential.8-10
Between 2005 and 2007, teams led by Gerald Pier showed that a deacetylated form of PNAG (dPNAG) elicited bacteria-killing