Humanized monoclonal anti-nuclear antibodies with enhanced binding affinity and tumor uptake are presented. Particularly preferred antibodies are site-directed mutants of H-CDR3 with up to about 8-fold improvement in affinity as compared to the non-humanized non-mutated form. In further preferred aspects, such humanized antibodies are employed in tumor necrosis targeted delivery of immune modulators, immune effectors, and other therapeutic or diagnostic agents.
