Abstract: A polyspecific anti-leukocyte antibody conjugate for targeting foci of leukocyte accretion comprises an immunoreactive polyspecific composite of at least two different substantially monospecific antibodies or antibody fragments, conjugated to at least one imaging agent, wherein at least two of said antibodies or antibody fragments specifically bind to different leukocyte cell types.A method for targeting an imaging agent to an inflammatory or infectious lesion comprises injecting a mammal parenterally with an effective amount for targeting of the above anti-leukocyte imaging conjugate.A therapeutic anti-leukocyte antibody-agent conjugate for targeting foci of leukocyte accretion comprises at least one immunoreactive substantially monospecific antibody or antibody fragment which specifically binds to at least one leukocyte cell type, conjugated to at least one therapeutic antimicrobial agent and/or radionuclide.

Abstract: A method of targeting a diagnostic or therapeutic agent to a focus of infection comprises injecting a patient infected with a pathogen parenterally with an antibody conjugate which specifically binds to an accessible epitope of the pathogen or of a pathogen-associated antigen accreted at the focus of infection, the antibody conjugate further comprising a bound diagnostic or therapeutic agent for detecting, imaging or treating the infection. Polyspecific composite conjugates enhance the efficacy of the method, which is especially useful for treating infections that are refractory towards systemic chemotherapy.