The present invention relates to methods of producing an antigenic response in which an antigen is contacted to an antigen-presenting cell, wherein the improvement comprises contacting the antigen-presenting cell with an A1 adenosine receptor activating agent in an amount sufficient to increase the antigenic response of the antigen-presenting cell to the antigen. The present invention further provides methods, compositions, combination therapies, imaging techniques, and diagnostic kits that may improve the diagnosis, prognosis, and/or survival of cancer patients, pathogen-infected patients, and infectious or non-infectious immune-deficient patients.
