Monoclonal Antibodies Specific for Ecdysone

Abstract

Two monoclonal antibodies specific for ecdysone were established. Mice (strain BALB/c) were immunized with 20-hydroxyecdysone conjugated with human serum albumin and subsequently the spleen cells were fused with murine P3Ul myeloma cells. The immunoglobulin isotypes of these monoclonal antibodies were IgGl. Both antibodies showed the highest cross-reactivity with ecdysone among ecdysteroids tested. Their association constants for ecdysone were 1.3×10¹⁰M^-1 and 0.9×10¹⁰M^-1, respectively. They recognized the differences in chemical groups at position 2 and 20 on the steroid carbonskeletal structure. Radiommunoassay using a monoclonal antibody (2-6D8G) showed that ecdysone in the range of 10 to 300 pg was measurable.