Development of an anti-idiotype monoclonal antibody mimicking the structure of lipopolysaccharide (LPS) inner-core determinants.

An anti-idiotype antibody has been developed which is specific for idiotypic determinants of a BALB/c mouse IgG3 monoclonal antibody (MAbY1-4A6) directed against the inner-core Kdo region of lipopolysaccharide (LPS). Armenian hamsters were immunized with MAbY1-4A6 and splenocytes from immunized animals fused with Sp2/0 myeloma cells. Eight clones secreting antibodies that bound to MAbY1-4A6, but not control IgG3, were identified and subcloned. Culture supernatants from one hybridoma, termed MAb4G2, contain monoclonal antibody that binds to the variable region of MAbY1-4A6 and dose-dependently inhibits binding of MAbY1-4A6 to Re chemotype rough mutant LPS (Re-LPS). This antibody also inhibits binding of three additional mouse monoclonal antibodies specific for the inner-core of Re-LPS. MAb4G2 also recognizes a significant proportion of antibodies present in polyclonal R-chemotype antisera generated in mice (Re-LPS) and rabbits (J5 Rc-LPS). Mice and hamsters immunized with MAb4G2 or Re-LPS generate antibodies which cross-react with both immunogens. Cumulatively, these data suggest that MAb4G2 can function as an internal image of the Kdo-specific monoclonal antibody, MAbY1-4A6, mimicking the antigenic structure and immunogenicity of a portion of the LPS inner-core Kdo region.