Ex vivo manipulation of the immune system for therapeutic purposes has shown incredible clinical promise with the advent of cell therapies such as Chimeric Antigen Receptor modified T-Cell Therapies (CAR-T). However expanding methods to manipulate cells beyond using plasmids and viruses requires a new delivery paradigm. Here we describe a microfluidic approach discovered at MIT where cells are mechanically deformed as they pass through a constriction smaller than the cell diameter. The resulting controlled application of compression and shear forces results in the formation of transient holes that enable the diffusion of material from the surrounding buffer directly into the cytosol. The method was recognized as one of the World Changing Ideas of 2014 by Scientific American since it has demonstrated the ability to deliver a range of material, such as nanoparticles and proteins to primary cells including embryonic stem cells and immune cells. This is in contrast to existing vector-based and physical methods that have limitations, including their reliance on exogenous materials or electrical fields, which can lead to toxicity or oncogenic off-target effects. Supporting the enabling potential of the new deformation based method, we previously reported that delivering protein transcription factors to primary fibroblasts produces a 10-fold improvement in induced pluripotent stem cell colony formation relative to electroporation and cell-penetrating peptides.

In this work we describe the use of the vector-free technology to deliver antigen protein directly to the cytoplasm of antigen presenting cells to drive a powerful antigen specific T-cell response. Current efforts to use antigen presenting cells to drive T-cell responses rely on an inefficient process called cross-presentation that relies on material escaping the endosome and entering the cytoplasm. We believe that by delivering antigen directly to the cytoplasm of antigen presenting cells we can overcome this long standing barrier and drive powerful and specific T-cell responses. Our results show that by adoptively transferring antigen presenting cells that have antigen delivered into them we can drive a significant T-cell response. Specifically, we found that this results in a ∼50x increase in antigen specific T-cells in vivo when compared to endocytosis. This advance has the potential to dramatically enhance the therapeutic potential of therapeutic vaccination with antigenic material for the treatment of a wide variety of cancers. Indeed, the ability to deliver structurally diverse materials to difficult-to-transfect primary cells indicate that this method could potentially enable many novel clinical applications.

Citation Format: Armon Sharei, Jonathan Gilbert, Darrell Irvine, Klavs Jensen, Robert Langer. Vector-free engineering of immune cells for adoptive cell therapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2293.