The Measurement of Low-Molecular-Weight, Non-Immunogenic Compounds by Immunoassay

The analysis of compounds by immunoassay requires an antibody preparation active against the compound of interest Small molecules (< 1000 daltons) do not themselves stimulate antibody formation. In order to produce the required antibodies, the small molecule (the hapten) must be covalently linked to a larger molecule (usually a protein) that is immunogenic and this conjugate used to immunise an animal. The antiserum thus generated will contain a mixture of antibodies, some of which will be capable of recognising the hapten even when free in solution. The application of such methods to the analysis of mammalian steroids resulted in the successful development of a number of immunoassays and revolutionised their determination (Abraham 1974). To date, immunological methods have been developed and applied in three major areas of plant research: