Booty et al. showed that, by comparison to antigen endocytosis by DCs, antigens directly delivered to the cytosol by gentle microfluidic squeezing triggered CD8+ T cells about 1000 times more efficiently. Activation was observed using squeezed cells of diverse and plentiful phenotypes (e.g., T cells, B cells, and splenocytes in mice; PBMCs in humans). In mice, squeezed cells loaded with tumor antigen resulted in T cell activation, tumor growth inhibition, and prolonged survival. These data suggest that, as highly efficient elicitors of CD8+ T cell responses, squeezed cells may have clinical potential as cancer therapeutics.
Contributed by Margot O’Toole
ABSTRACT: CD8(+) T cell responses are the foundation of the recent clinical success of immunotherapy in oncologic indications. Although checkpoint inhibitors have enhanced the activity of existing CD8(+) T cell responses, therapeutic approaches to generate Ag-specific CD8(+) T cell responses have had limited success. Here, we demonstrate that cytosolic delivery of Ag through microfluidic squeezing enables MHC class I presentation to CD8(+) T cells by diverse cell types. In murine dendritic cells (DCs), squeezed DCs were _1000-fold more potent at eliciting CD8(+) T cell responses than DCs cross-presenting the same amount of protein Ag. The approach also enabled engineering of less conventional APCs, such as T cells, for effective priming of CD8(+) T cells in vitro and in vivo. Mixtures of immune cells, such as murine splenocytes, also elicited CD8(+) T cell responses in vivo when squeezed with Ag. We demonstrate that squeezing enables effective MHC class I presentation by human DCs, T cells, B cells, and PBMCs and that, in clinical scale formats, the system can squeeze up to 2 billion cells per minute. Using the human papillomavirus 16 (HPV16) murine model, TC-1, we demonstrate that squeezed B cells, T cells, and unfractionated splenocytes elicit antitumor immunity and correlate with an influx of HPV-specific CD8(+) T cells such that >80% of CD8s in the tumor were HPV specific. Together, these findings demonstrate the potential of cytosolic Ag delivery to drive robust CD8(+) T cell responses and illustrate the potential for an autologous cell-based vaccine with minimal turnaround time for patients.
Author Info: (1) SQZ Biotechnologies, Watertown, MA. (2) SQZ Biotechnologies, Watertown, MA. (3) SQZ Biotechnologies, Watertown, MA. (4) SQZ Biotechnologies, Watertown, MA. (5) SQZ Biotechnolog
Author Info: (1) SQZ Biotechnologies, Watertown, MA. (2) SQZ Biotechnologies, Watertown, MA. (3) SQZ Biotechnologies, Watertown, MA. (4) SQZ Biotechnologies, Watertown, MA. (5) SQZ Biotechnologies, Watertown, MA. (6) SQZ Biotechnologies, Watertown, MA. (7) SQZ Biotechnologies, Watertown, MA. (8) SQZ Biotechnologies, Watertown, MA. (9) SQZ Biotechnologies, Watertown, MA. (10) SQZ Biotechnologies, Watertown, MA. (11) SQZ Biotechnologies, Watertown, MA. (12) SQZ Biotechnologies, Watertown, MA. (13) SQZ Biotechnologies, Watertown, MA. (14) SQZ Biotechnologies, Watertown, MA. (15) SQZ Biotechnologies, Watertown, MA. (16) SQZ Biotechnologies, Watertown, MA. (17) SQZ Biotechnologies, Watertown, MA. (18) SQZ Biotechnologies, Watertown, MA. (19) SQZ Biotechnologies, Watertown, MA. (20) SQZ Biotechnologies, Watertown, MA. (21) Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA. (22) Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA. (23) Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA. (24) SQZ Biotechnologies, Watertown, MA. (25) SQZ Biotechnologies, Watertown, MA. (26) SQZ Biotechnologies, Watertown, MA. (27) SQZ Biotechnologies, Watertown, MA. (28) SQZ Biotechnologies, Watertown, MA. (29) Department of Immunology, Harvard Medical School, Boston, MA. Ragon Institute of MGH, MIT, and Harvard, Boston, MA. Center for Immune Imaging at Harvard Medical School, Boston, MA. (30) Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA. (31) Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA. David Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA. (32) Roche Innovation Center Basel, Roche Pharmaceutical Research and Early Development, Basel, Switzerland; and. (33) Roche Innovation Center Zurich, Roche Pharmaceutical Research and Early Development, Schlieren, Switzerland. (34) Roche Innovation Center Zurich, Roche Pharmaceutical Research and Early Development, Schlieren, Switzerland. (35) SQZ Biotechnologies, Watertown, MA. (36) SQZ Biotechnologies, Watertown, MA. (37) SQZ Biotechnologies, Watertown, MA; scott.loughhead@sqzbiotech.com.
