Vector-Free Engineering of Antigen Presenting Cells for Adoptive Immunotherapies for the Treatment of Cancer

Abstract In recent years, ex vivo manipulation of primary cells has shown immense clinical potential with the advent of adoptive T cell therapies. Conventional methods for ex vivo manipulation, however, are not without limitations. They typically rely on the application of electrical fields or exogenous materials such as viral vectors and plasmids, which can increase the potential for cellular toxicity and off-target effects. To overcome such limitations, we have developed an approach using our CellSqueeze Technology that causes temporary membrane disruption as cells are passed through a microfluidic constriction. While the membrane is disrupted, material in the surrounding buffer can diffuse directly into the cytosol. This system has demonstrated efficacy in patient-derived cells, such as stem cells and immune cells, and with a variety of molecules that are difficult to address with alternative methods. In this work, we describe the use of our vector-free technology to deliver antigens directly to the cytoplasm of antigen-presenting cells (APCs) to drive potent antigen-specific CD8 T cell responses. Conventional methods for eliciting T cell responses with APCs typically rely on cross-presentation, which can be inefficient and require lengthy cultures. Our results show that murine APCs processed with our CellSqueeze Technology can stimulate enhanced antigen-specific T cell responses in vitro and in vivo by at least 3-fold, when compared to responses stimulated by endocytosis controls. Additionally, we show translation of these significant advantages of the CellSqueeze Technology to human APCs, reinforcing the exciting clinical potential of CellSqueeze for adoptive cell therapy.