Enhanced Antigen-Specific Antibody and Cytokine Responses When Targeting Antigen to Human FcGAMMA Receptor Type I Using an Anti-Human FcGAMMA Receptor Type I-Streptavidin Fusion Protein in an Adjuvant-Free System

Abstract

There is a continuing need for alternatives to current human adjuvants. Recombinant protein vaccines, which target antigen to human Fc gamma receptor type I (hFcγRI) on hFcγRI-expressing antigen presenting cells, provide one potential alternative. Using a recombinant anti-hFcγRI-antigen fusion protein and adjuvant independent mouse model, we demonstrate enhanced antigen-specific antibody responses to low doses of antigen, when targeting antigen to hFcγRI in vivo. Enhanced antibody production to hFcγRI-targeted antigen is evident in both primary and secondary immune responses, as compared to that of non-targeted antibody. Furthermore, antigen isotype and cytokine responses following immunization with hFcγRI-targeted antigen, suggest enhancement of both Th1 and Th2 responses.