1 research outputs found
Serological characterization of the enterobacterial common antigen substitution of the lipopolysaccharide of "Yersinia enterocolitica" O:3
Enterobacterial common antigen (ECA) is a polysaccharide present in all members of
Enterobacteriaceae anchored either via phosphatidylglycerol (PG) or LPS to the outer leaflet of
the outer membrane (ECAPG and ECALPS, respectively). Only the latter form is ECAimmunogenic.
We previously demonstrated that Yersinia enterocolitica O: 3 and its rough (Ospecific
polysaccharide-negative) mutants were ECA-immunogenic, suggesting that they
contained ECALPS; however, it was not known which part of the LPS core region was involved in
ECA binding. To address this, we used a set of three deep-rough LPS mutants for rabbit
immunization. The polyvalent antisera obtained were: (i) analysed for the presence of anti-LPS and
anti-ECA antibodies; (ii) treated with caprylic acid (CA) to precipitate IgM antibodies and protein
aggregates; and (iii) adsorbed with live ECA-negative bacteria to obtain specific anti-ECA
antisera. We demonstrated the presence of antibodies specific for both ECAPG and ECALPS in all
antisera obtained. Both CA treatment and adsorption with ECA-negative bacteria efficiently
removed anti-LPS antibodies, resulting in specific anti-ECA sera. The LPS of the ECALPS-positive
deepest-rough mutant contained only lipid A and 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo)
residues of the inner core, suggesting that ECALPS was linked to the Kdo region of LPS in Y.
enterocolitica O:3