BINDING DIVERSITY OF MONOCLONAL-ANTIBODIES TO ALPHA(2-]8) POLYSIALIC ACID CONJUGATED TO OUTER-MEMBRANE VESICLE VIA ADIPIC ACID DIHYDRAZIDE

Murine monoclonal antibodies (mAbs) were generated using group B Neiss eria meningitidis and Escherichia coli K1 polysaccharides (PSs) conjug ated to outer membrane vesicle (OMV) via adipic acid dihydrazide, and were used to identify the immunodeterminants expressed on these capsul ar PSs. Ten mAbs representative of IgM and all subclasses of IgG were obtained which recognized diverse immunodeterminants on alpha(2 --> 8) polysialic acid (PSA). The specificity of mAbs to different antigenic determinants was assessed by their differential binding to PSA attach ed to a solid phase by different methods and confirmed by absorption s tudies. Two mAbs from the E. coli K1 fusion were directed to the O-ace tyl epitope and the rest reacted with both the PSs only when attached to a solid phase by certain means. The methods by which PSA was coated on the solid phase had an impact on the epitope expression and bindin g pattern. At the concentrations used, the O-acetyl-specific mAbs, IgG 1 and IgG3 mAbs were not bactericidal against group B N. meningitidis, whereas other mAbs were. The conjugates B and K1 PSs present to the m urine immune system different antigenic determinants, some of which el icit bactericidal antibodies.