Production and characterization of cross-reactive monoclonal antibodies to sweet proteins.
We report on the characterization of a panel of eight murine monoclonal antibodies induced by immunization with the sweet protein monellin and which display cross-reactivity with thaumatin, another sweet natural molecule. Cross-reactivity was determined based on direct binding assays and antigen competition experiments. Interestingly, half of antibodies bound thaumatin more than monellin, the immunizing antigen. The relatedness between the binding sites of the eight monoclonal antibodies was assessed by cross-competition of the binding of monellin to individual monoclonal antibodies. Antibodies that bound in a similar way monellin and thaumatin were on average the best inhibitors. All antibodies also bound Sp1, a genetically-engineered single chain monellin. These studies demonstrate that the immune repertoire encodes for specificities that are common to monellin and thaumatin despite the fact that the two molecules share little, if any, structural homology. These results are discussed in relation to the use of cross-reactive antibodies to generate anti-receptor antibodies via idiotypic immunization.
Antonenko
S
S
Department of Medicine and Cancer Center, University of California, San Diego, La Jolla 92093-0961.
Zanetti
M
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000302:isolation & purification; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D051379:Mice; D008807:Mice, Inbred BALB C; D010940:Plant Proteins / Q000276:immunology*; D013549:Sweetening Agents
D000911:Antibodies, Monoclonal; D010940:Plant Proteins; D013549:Sweetening Agents; C002541:monellin protein, Dioscoreophyllum cumminsii; C003427:thaumatin protein, plant