Abstract: Methods for improved targeting of antibody, antibody fragments, peptides hormones, steroid hormones and conjugates thereof are disclosed. Enhanced delivery to target cells of antibodies or fragments thereof or other receptor-mediated delivery system, such as peptide, specific for a population of cells of a mammal comprises steps of administering to said mammal an adequate dosage of blocking antibodies or fragments thereof or other receptor-mediated delivery system, such as peptide, and administering to said mammal an effective dosage of said antibodies or fragments thereof or other receptor-mediated delivery system, such as peptide, specific for said population of cells. In the preferred embodiment, the specific antibodies are monoclonal antibodies directed toward tumor-associated antigen in man.

Abstract: Diagnostic or therapeutic agents are attached to two or more antibody species having non-overlapping patterns of cross-reactivity to increase the relative amount of the active agent(s) delivered to desired target cells compared to non-target cells. The agents may be attached to monoclonal antibodies which bind to cancer cells so that a higher percentage of the active agent(s) localize on the target cells compared to each type of cross-reactive normal tissue.

Abstract: Methods are disclosed for improving the efficiency of elicitation of monoclonal antibodies to glycoprotein antigens and tumor-associated antigens, and for inducing the production of IgG class monoclonal antibodies, in particular the IgG.sub.3 subclass. The methods involve the use of a lectin/extract immunogen to stimulate the production of the desired monoclonal antibodies.

Abstract: Cells such as genetically modified cells, e.g., hybridoma, which secrete an antigenic substance are encapsulated within capsule membranes having pores of dimensions sufficient to permit efflux of the antigens secreted by the cells but insufficient to permit traverse of the cells. The capsules are injected into an experimental animal where antigen passing through the pores of the capsule membrane induces lymphocytes to produce antibodies complementary to the antigen. The antibody may be harvested from the circulatory system of the animal. Preferably, lymphocytes are sampled from, e.g., the spleen of the animal, fused with a malignant cell line to produce a hybridoma which synthesizes the antibody in vivo, and the hybridoma is cultured to produce large quantities of monoclonal antibody.