Immunological Evidence for a Cell Surface Receptor of Victorin Using Anti-Victorin Anti-Idiotypic Polyclonal Antibodies. Kazuya Akimitsu. Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824 U.S.A. L. Patrick Hart(1,2), and Jonathan D. Walton(1,3). (1)Department of Botany and Plant Pathology, (2)Pesticide Research Center, and (3)DOE-Plant Research Laboratory, Michigan State University, East Lansing 48824 U.S.A. MPMI 6:429-433. Accepted 9 March 1993. Copyright 1993 The American Phytopathological Society.

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.