Nanoparticle-based compositions, assays, kits, methods and platforms for delivering an antigen (peptides, proteins) or a nucleic acid encoding an antigen to professional APCs (PAPCs) result in the generation of autologous APCs that present a natural peptide repertoire of the antigen for use in assessing the efficacy of a vaccine (e.g., a cytotoxic T lymphocyte (CTL) response to a particular antigen) or other therapy or intervention (cell-based therapy, adjuvant therapy, etc.). The compositions, kits, assays and methods also can be used for delivering a drug or biologic or portion thereof to APCs for assessing the immunogenicity of drugs and biologics. The composition, kits, assays and methods involve the combined use of MHC targeting, universal DR binding peptides (e.g., PADRE, HA) with charged (e.g., positively-charged) highly branched polymeric dendrimers (e.g., PAMAM and other dendrimers) as vehicles for the targeted delivery of nucleic acids, peptides, biologics, drugs, or polypeptides to APCs, giving rise to a new nanoparticle-based method for assessing the immune response (CTL response) to a vaccination or other therapy or intervention, or for assessing the immunogenicity of a biologic or drug. Targeted delivery of nucleic acids, peptides, biologics, drugs, or polypeptides to APCs for effective expression and processing generates more physiologically relevant target antigens for evaluation of cell-mediated immune responses to vaccination, for example, and provides a low-cost approach for rapid generation of reagents and development of assay systems for more accurate profiling of immunological responses to infection, immunization, and other therapies or interventions. Immunoevaluation kits using targeted nanoparticle-based antigen delivery are described herein.