Altered antigenicity is seen in the lipopolysaccharide profile of non-serotypeable Actinobacillus actinomycetemcomitans strains

Non-serotypeable. Actinobacillus actinomycetemcomitans strains may be deriv ed from the serotypeable ones. In the present study, we compared the outer membrane proteins (OMPs) and lipopolysaccharides (LPSs) of serotypeable and non-serotypeable A. actinomycetemcomitans strains (n=24) OF the same genot ype in the same subject (n=6) to find out if alterations on the cell-surfac e contribute to the non-serotypeability. Serotypeable and non-serotypeable A. actinomycetemcomitans strains showed great similarity in the OIL IP patt erns both within and between subjects. Using serotype-specific antisera, cl ear immunoblotting LPS profiles in the O-antigenic region were seen in sero type b and c strains but not in non-serotypeable strains from the same subj ects. The results suggest that changes in LPS lead to the altered antigenic ity of non-serotypeable A actinomycetemcomitans strains. (C) 2000 Federatio n of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.