An enzyme-linked immunosorbent assay for the antineoplastic agent vincristine

An enzyme-linked immunosorbent assay for vincristine was developed, based on a new procedure for synthesizing the hapten-protein conjugate. In both the immunogen and the enzyme tracer a spacer group was introduced between the hapten and protein, and the vincristine was coupled at a site far from its functional groups. The antibody produced proved to be exceptionally specific as compared with previous immunoassays for bis-indole alkaloids. Thousandfold antibody dilutions could be used and samples at the femtomole range were assayable. Applications of the method to patient plasma samples and to plant material are described.