Radioimmunoassay system for the detection of vinblastin

A radioimmunoassay system for the detection of vinblastin has been developed. Vinblastin, one of the indole alkaloids contained in the Catharanthus roseus, is a useful anti-tumor substance. It is produced industrially by means of the extraction from C. roseus. Recently, the tissue culture of the C. roseus has been investigated by several researchers for the purpose of producing vinblastin. In these studies, it proves very difficult to determine the vinblastin content in the intercellular alkaloids of C. roseus, since the level of the content is very low ranging from 500 pg/ml to 5 ng/ml. For the detection of vinblastin, the bio-assay system has been employed. This method, however, is not sufficient in sensitivity, and requires much time and complicated processes, due to the use of the tumor cell. To overcome these disadvantages, radioimmunoassay system of vinblastin is attempted, where it is most important to get a specific antibody to vinblastin. Thus vinblastin was conjugated to bovine serum albumin (BSA) and then immunized to three rabbits. A highly specific antibody to vinblastin was obtained from one of these rabbits. By use of this antibody and 3H labbeled vinblastin, an effective radioimmunoassay system with high sensitivity (10 times as sensitive as the bio-assay), specificity, reproducibility and simplicity, has been established. (author)