A monoclonal antibody recognizing the 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) trisaccharide αKdo(2→4)αKdo(2→4)αKdo of Chlamydophila psittaci 6BC lipopolysaccharide

Abstract

A monoclonal antibody (mAb) S45-18 was generated against a synthetic neoglycoconjugate containing the trisaccharide αKdo (2→4)αKdo(2→4)αKdo (Kdo, 3-deoxy-D-manno-oct-2-ulopyranosonic acid) which represents a structure of the lipopolysaccharide (LPS) from Chlamydophila psittaci 6BC. The antibody was characterized by binding and inhibition assays in ELISA using: (i) the immunizing antigen and chemically synthesized derivatives thereof; (ii) chlamydial elementary bodies (EB); and (iii) LPS of Chl. psittaci 6BC and Chlamydia trachomatis L2The specificity was determined in comparison to that of mAb S25-23 recognizing the αKdo(2→8)αKdo(2→4)αKdo trisaccharide which represents an epitope shared by all species of the family. MAb S45-18 bound to an epitope of the structure αKdo(2→4)αKdo(2→4)αKdo, with lower reactivity with the (2→8)-(2→4)-linked analog. Using chlamydial EB or LPS, mAb S45-18 bound preferentially to LPS and EB of Chl. psittaci. Therefore, Chl. psittaci LPS contains, in addition to the known genus-specific epitope, a species-specific epitope.