Cyclophosphamide treatment used to manipulate the immune response for the production of monoclonal antibodies.

After immunization with a complex mixture of antigens, a considerable bias toward obtaining monoclonal antibodies to immunodominant determinants exists. By selectively killing antigen-stimulated lymphocytes, the cytotoxic drug cyclophosphamide can be used to manipulate the bias of the normal immune response. Cyclophosphamide has been used to tolerize mice to one set of antigens followed by immunization with a similar but slightly different set of antigens. This approach yields an enhanced frequency of antibodies that distinguish the two sets of antigens. Cyclophosphamide treatment has also allowed us to produce monoclonal antibodies to weakly immunogenic glycosaminoglycans and to obtain a high frequency of apparently anti-idiotypic antibodies.