A method and pharmaceutical composition is provided for enhancing theendogenous immune response-mediated elimination of a population of pathogeniccells in a host animal wherein the pathogenic cells preferentially express,uniquely express, or overexpress a binding site for a particular ligand. Theinvention comprises administering the ligand conjugated to an immunogen to ahost animal harboring the population of pathogenic cells. Antibodies,preexisting or administered to the host animal to establish a passiveimmunity, directed against the immunogen bind to the ligand-immunogenconjugate resulting in elimination of the pathogenic cell by the host's immuneresponse. At least one additional therapeutic factor is administered selectedfrom the group consisting of a cell killing agent, a tumor penetrationenhancer, a chemotherapeutic agent, antimicrobial agent, a cytotoxic immunecells, and a compound capable of stimulating an endogenous immune responsewherein the compound does not bind to the ligand-immunogen conjugate.
