Abstract: The present invention relates to conjugates of diagnostic or therapeutic principles, such as drugs, toxins, chelators, boron compounds and detectable labels, to an antibody, in which the diagnostic or therapeutic principle is first loaded onto a polymer carrier such as an aminodextran or a polypeptide of at least 50 amino acids in length, and this intermediate is in turn site-specifically conjugated to a targeting antibody such as an antitumor antibody. The resultant conjugate substantially retains the immunoreactivity of the antibody, and targets the diagnostic or therapeutic principle to a target tissue or organ where the diagnostic or therapeutic effect is realized.

Abstract: Antibodies specific to specific CEA epitopes and epitopes of CEA-cross-reactive antigens are provided. Methods of use of these antibodies and purified CEA antigens and cross-reactive antigens are also provided.

Abstract: Immunoassay system for determining the amount of a polyvalent ligand in a liquid test sample, and based on:(a) an insoluble phase to which is bound a separation specific binding substance which does not bind said ligand;(b) a capture specific binding substance which specifically binds said ligand, and which is itself specifically bound by said spearation specific binding substance; and(c) a probe specific binding substance which specifically binds said ligand at a site which is accessible when said ligand is bound to said capture specific binding substance, said probe specific binding substance being not substantially bound by said separation specific binding substance, and being detectable by at lease one detection procedure.

Abstract: A conjugate of methotrexate to an antibody is prepared by loading methotrexate onto an aminodextran, then specifically conjugating the polymer carrier to the carbohydrate portion of an antitumor antibody, using a reduced Schiff base linkage. The conjugate is useful for tumor targeted therapy.