IMMUNOLOGICAL EVIDENCE FOR A CELL-SURFACE RECEPTOR OF VICTORIN USING ANTI-VICTORIN ANTIIDIOTYPIC POLYCLONAL ANTIBODIES

Anti-victorin anti-idiotypic polyclonal antibodies were raised in rabbits immunized with an anti-victorin polyclonal antibody-ovalbumin conjugate. The presence of anti-victorin anti-idiotypic antibodies in the serum was examined by the inhibition of victorin-horseradish peroxidase (HRP) binding against anti-victorin antibody in a direct enzyme-linked immunosorbent assay (ELISA). Victorin-HRP binding in a direct ELISA was inhibited 84% by addition of a tenfold diluted anti-victorin anti-idiotypic serum. Sera from nonimmunized rabbits did not show significant inhibition. The anti-idiotypic serum diluted 20-fold, induced callose synthesis in protoplasts from victorin-sensitive but not insensitive oat cultivars. When anti-idiotypic antibodies were added simultaneously with 60 pg of victorin per milliliter, they inhibited victorin-induced callose synthesis by 68%. Since anti-idiotypic antibodies are presumed to be too large to enter the cell, these results indicate that victorin acts at the surface of cells.