Induction of tumor antigen-specific cytotoxic T cell responses in naive mice by latex microspheres-based artificial antigen-presenting cell constructs

Latex microspheres-based artificial antigen-presenting cell constructs (aAPCs) are proved to be valuable tools to expand T cells ex vivo for adoptive cell therapy, but little is known about their potential for active immunization. In this report, HLA-A2/peptide tetramers were generated and co-coated with anti-mouse CD28 monoclonal antibody onto surface of cell-sized latex microspheres followed by immunization of naive HLA-A2/K-b transgenic mice. Five- to six-fold expansion of tumor antigen-specific CTLs was observed in the spleen after three rounds of immunization. The consequent splenocytes can efficiently recognize endogenously expressed tumor antigen on the surface of human target cells and cytolyze the tumor cells in an antigen-specific manner. This report provides initially the experimental evidence that latex micro spheres-based aAPCs can effectively prime antigen-specific CTL proliferation and cytolysis in naive mice. This may contribute to a better insight into the potential of micro sphere s-based aAPCs for active immunization. (C) 2007 Elsevier Inc. All rights reserved.