The present invention relates to pharmaceutical compositions that are useful for the prevention and treatment of infectious diseases, primary and metastatic neoplastic diseases (i.e., cancer), neurodegenerative or amyloid diseases, or any other disease wherein the treatment of such disease would be improved by an enhanced immune response, and methods of formulating the compositions. The compositions comprise an immunoreactive reagent (i.e., an antigen binding protein comprising an antigen binding region and a region or regions of an antibody that mediate antibody dependent immunological processes) and a saponin. The present invention also relates to methods of using the compositions of the invention for the prevention and/or treatment of infectious diseases, primary and metastatic neoplastic diseases (i.e., cancer), neurodegenerative or amyloid diseases, or any other disease wherein the treatment of such disease would be improved by an enhanced immune response.