Production of monoclonal antibodies to a steroid plant growth regulator

Abstract

The active component of the brassin complex of higher plants has been shown to be a C28 steroidal lactone called brassinolide. This compound has been shown to enhance both cell division and cell growth. Monoclonal antibodies directed against a synthetic brassinosteroid have been produced in CAF1 mice. The mice were immunized with a saline solution containing the steroid hapten noncovalently bound to chloroform–methanol extracted fetal calf serum. Hybridomas were generated by fusing primed mouse spleen cells with SP2/0 myeloma cells. Sixty-one hybridoma clones were screened; four of these gave positive enzyme-linked immunosorbent assay (ELISA) values with the brassinosteroid hapten. One of these clones produced an immunoglobulin G antibody with a high specificity for the synthetic antigen. The brassinosteroid hapten which differs from the natural brassinolide by the position of a methyl group on the C24 carbon gave a considerably higher ELISA value than the natural growth regulator and several other plant steroids. The distribution of brassinolide in Brassica napus tissues was examined by ELISA with the monoclonal antibody.