Adoptive cell therapy (ACT) has become an increasingly attractive method for treating patients with solid tumors due to its impressive response rate; that said, the costs and complexity of current cellular approaches for expansion of tumor-specific T cells have limited accessibility of this therapy. Significant progress has been made in scalable, acellular technologies for expanding tumor-specific CD8 T cells. However, no analogous acellular platforms for expansion of CD4 T cells exist, despite overwhelming preclinical and clinical evidence that CD4 T cells are central to antitumor immune responses and can augment CD8- based therapies. The goal of the proposed project is to investigate the application of a novel Class II artificial antigen presenting cell (aAPC) for expansion of functional, polyclonal endogenous tumor-specific CD4 T cells for ACT as well as potential synergies with endogenous CD8 T cells. The platform, which consists of a 50 nm paramagnetic iron dextran nanoparticle conjugated with Class II Major Histocompatibility Complex proteins and costimulatory molecules, will allow us 1) to enrich and expand rare murine and human tumor-specific CD4 T cells to clinically relevant levels, and 2) to facilitate dendritic cell (DC) independent T cell help. In turn, the Class II aAPC will allow us for the first time to monitor both the antitumor efficacy and T cell receptor dynamics of ACT with polyclonal CD4 or combined CD4 and CD8 T cells in mice. To accomplish these goals, the project will proceed in three phases. First, we will investigate the in vitro function and in vivo antitumor efficacy of aAPC-expanded polyclonal CD4 T cells specific to foreign and self-antigens, OVA and Trp1 with B16-OVA and B16-F10 melanoma models, respectively. Second, we will apply a modular human Class II aAPC, capable of expanding a range of antigen-specific CD4 T cells through HLA molecules loaded with thrombin-cleavable peptides, to expand functional tumor-antigen NY-ESO-1 specific CD4 T cells from HLA DR1 and DP4 donors. Finally, we will combine the Class I and Class II aAPC technologies to investigate DC independent in vitro and in vivo antitumor synergies of combined antigen-specific mouse and human CD4 and CD8 culture, using B16-OVA and B16-F10 for mouse T cells, and the human SK-MEL-37 (A2+/NY-ESO-1+) melanoma cell line for human T cells. If successful, this proposal will deliver a novel acellular approach for polyclonal CD4 or combined CD4 and CD8 ACT and will provide insight into alternative mechanisms of T cell help, with potential clinical ramifications for ex vivo CD8 T cell expansion.
The proposed research seeks to apply a novel nanoparticle-based platform for expansion of endogenous polyclonal populations of tumor-specific CD4 T cells for adoptive cell therapy. Through the platform, the proposed research will investigate the antitumor function of antigen- specific polyclonal CD4 or combined CD4 and CD8 T cells targeting foreign versus self-antigens in mouse melanoma adoptive transfer models. The technology will also be adapted to expand human tumor-specific CD4 T cells either alone or in combination with CD8 T cells to observe the functional implications of nanoparticle-based co-activation in vitro and in vivo and to demonstrate the clinical relevance of this technology.
