Abstract: Disclosed are methods of stimulating in a subject an immune response to an antigen to which the immune response is targeted. This method includes the step of administering to the subject a binding agent which binds a surface receptor of an antigen-presenting cell, in some instances without being blocked substantially by the natural ligand for the surface receptor, and an antigen to which the immune response is targeted, in a physiologically acceptable medium to the subject. Also disclosed are molecular complexes including the binding agent coupled to an antigen.

Abstract: Disclosed are methods of stimulating in a subject an immune response to an antigen to which the immune response is targeted. This method includes the step of administering to the subject a binding agent which binds a surface receptor of an antigen-presenting cell, in some instances without being blocked substantially by the natural ligand for the surface receptor, and an antigen to which the immune response is targeted, in a physiologically acceptable medium to the subject. Also disclosed are molecular complexes including the binding agent coupled to an antigen.

Abstract: Disclosed are methods of stimulating in a subject an immune response to an antigen to which the immune response is targeted. This method includes the step of administering to the subject a binding agent which binds a surface receptor of an antigen-presenting cell, in some instances without being blocked substantially by the natural ligand for the surface receptor, and an antigen to which the immune response is targeted, in a physiologically acceptable medium to the subject. Also disclosed are molecular complexes including the binding agent coupled to an antigen.

Abstract: Bispecific molecules comprising a target cell specific ligand and an effector cell specific antibody or functional antibody fragment are disclosed.

Abstract: Disclosed are methods of stimulating in a subject an immune response to an antigen to which the immune response is targeted. This method includes the step of administering to the subject a binding agent which binds a surface receptor of an antigen-presenting cell, in some instances without being blocked substantially by the natural ligand for the surface receptor, and an antigen to which the immune response is targeted, in a physiologically acceptable medium to the subject. Also disclosed are molecular complexes including the binding agent coupled to an antigen.

Abstract: Monoclonal antibodies which react specifically to Fc receptor of human effector cells are disclosed. Binding of the antibodies to the receptor is not blocked by human immunoglobulin G. The antibodies are useful for targeting human effector cells (e.g. macrophages) against a target cell (e.g. a cancer cell, an infectious agent, etc.) For this purpose, bifunctional antibodies or heteroantibodies can be constructed containing the binding region derived from an anti-Fc receptor antibody and the binding region of a target-specific antibody. Targeted effector cells can be used to kill target cells by cell mediated antibody dependent cytolysis.

Abstract: Bispecific molecules which react both with the high-affinity Fc.gamma. receptor of human effector cells and with a target cell surface antigen are disclosed. Binding of the molecules to the Fc receptors found on effector cells is not blocked by human immunoglobulin G. The molecules are useful for targeting human effector cells (e.g. macrophages) against cells bearing the target antigen. For this purpose, bispecific molecules can be constructed containing the binding region derived from an anti-Fc.gamma. receptor antibody and the binding region derived from an antibody specific for the target antigen. Targeted effector cells can be used to destroy cells bearing the target cell surface antigen by cell-mediated antibody dependent cytolysis and by complement-fixation.

Abstract: Binding agents which bind specifically to a receptor for human IgA, including monoclonal antibodies which react specifically to Fc receptor for IgA of human effector cells are disclosed. The binding agents, e.g., antibodies are useful for targeting human effector cells (e.g. macrophages) against a target cell (e.g. a cancer cell, an infectious agent, etc.). For this purpose, bifunctional antibodies or heteroantibodies can be constructed containing the binding region derived from an anti-Fc-alpha receptor antibody and the binding region of a target-specific antibody. Targeted effector cells can specifically lyse target cells.

Abstract: Bispecific molecules which react both with the high-affinity Fc.gamma. receptor (Fc.gamma.RI) of effector cells and with the human immunodeficiency virus (HIV), or component thereof are disclosed. Binding of these bispecific molecules to the Fc.gamma.RI is not blocked by the binding of the Fc region of IgG to that same receptor, as the bispecific molecules are specific for an epitope on the Fc.gamma.RI distinct from the Fc binding epitope. The bispecific molecules are useful for targeting human effector cells to a target on HIV. Also disclosed are methods of treating HIV infection using these bispecific molecules.

Abstract: Bispecific molecules comprising a non-immunoglobulin tumor cell specific ligand and an antibody which binds the Fc receptor of an effector cell at a site that is not inhibited by endogenous immunoglobulin are disclosed. The bispecific molecules can be used to induce a specific antibody dependent effector cell-mediated cytotoxicity against tumor cells, such as small cell lung carcinoma (SCLC) cells, either in vivo or in vitro.

Abstract: Bispecific molecules which react both with an Fc.gamma. receptor for immunoglobulin G (IgG) of human effector cells and with either human low density lipoprotein (LDL), or fragment thereof, or human high density lipoprotein (HDL), or a fragment thereof, are disclosed. The bispecific molecules bind to an Fc.gamma. receptor without being blocked by the binding of IgG to the same receptor. The bispecific molecules having a binding specificity for human LDL are useful for targeting human effector cells for degradation of LDL in vivo. The bispecific molecules of the present invention which have a binding specificity for human HDL are useful for targeting human HDL to human effector cells such that the HDL takes up cholesterol from the effector cells. Also disclosed are methods of treating atherosclerosis using these bispecific molecules.

Abstract: Monoclonal antibodies which react specifically to Fc receptor of human effector cells IgG are disclosed. Binding of the antibodies to the receptor is not blocked by human immunoglobulin G. The antibodies are useful for targeting human effector cells (e.g. macrophages) against a target cell (e.g. a cancer cell, an infectious agent, etc.) For this purpose, bifunctional antibodies or heteroantibodies can be constructed containing the binding region derived from an anti-Fc receptor antibody and the binding region of a target-specific antibody. Targeted effector cells can be used to kill target cells by cell mediated antibody dependent cytolysis.

Abstract: Monoclonal antibodies which react specifically to Fc receptor for IgA of human effector cells, such as monocytes, polymorphonuclear cells and macrophages, are disclosed.

Abstract: Monoclonal antibodies specific for the high affinity (72 K.D.) F.sub.c receptor on human monocytes are diclosed. The monoclonal antibodies do not block normal IgG binding to the receptor.