| abstract |
In producing an antibody using a low molecular substance as an antigen, it is necessary to immunize with an immunogen which is prepared by binding the antigen to protein. Therefore, it is difficult to produce an antibody having a high affinity to the antigen. According to the present invention, investigations were made, paying attention to the molecular structure, especially the structure at the site binding to protein, of the antigen in production of the immunogen. As the result, there is used a process which comprises preparing an antigen derivative (e.g., aminobutyl amphetamine) using a compound (e.g., amphetamine) having such a structure that an alkyl group of the desired antigen (e.g., methamphetamine) is replaced with hydrogen atom, and then binding the antigen derivative with protein. Immunization using the thus obtained immunogen gives an antibody having a high affinity to methamphetamine and improved sensitivity of immunoassay by about 1000 times. Furthermore, by this immunogen, a monoclonal antibody having a high affinity to methamphetamine can be produced. |