ABSTRACT
Checkpoint inhibitors and T-cell therapies have highlighted the critical role of T cells in anti-cancer immunity. However, limitations associated with these treatments drive the need for alternative approaches. Here, we engineer red blood cells into artificial antigen-presenting cells (aAPCs) presenting a peptide bound to the major histocompatibility complex I, the costimulatory ligand 4-1BBL, and interleukin (IL)-12. This leads to robust, antigen-specific T-cell expansion, memory formation, additional immune activation, tumor control, and antigen spreading in tumor models in vivo. The presence of 4-1BBL and IL-12 induces minimal toxicities due to restriction to the vasculature and spleen. The allogeneic aAPC, RTX-321, comprised of human leukocyte antigen-A*02:01 presenting the human papilloma virus (HPV) peptide HPV16 E711-19, 4-1BBL, and IL-12 on the surface, activates HPV-specific T cells and promotes effector function in vitro. Thus, RTX-321 is a potential 'off-the-shelf' in vivo cellular immunotherapy for treating HPV + cancers, including cervical and head/neck cancers.
Subject(s)
Antigen-Presenting Cells/transplantation , Cell Engineering/methods , Erythrocytes/immunology , Immunotherapy, Adoptive/methods , Neoplasms/therapy , 4-1BB Ligand/genetics , 4-1BB Ligand/immunology , 4-1BB Ligand/metabolism , Animals , Antigen-Presenting Cells/immunology , Antigen-Presenting Cells/metabolism , Cell Line, Tumor , Coculture Techniques , Disease Models, Animal , Erythrocytes/metabolism , Female , HLA-A2 Antigen/genetics , HLA-A2 Antigen/immunology , HLA-A2 Antigen/metabolism , Histocompatibility Antigens Class I/genetics , Histocompatibility Antigens Class I/immunology , Histocompatibility Antigens Class I/metabolism , Humans , Interleukin-12/genetics , Interleukin-12/immunology , Interleukin-12/metabolism , Lymphocyte Activation , Neoplasms/immunology , Papillomavirus E7 Proteins/genetics , Papillomavirus E7 Proteins/immunology , Papillomavirus E7 Proteins/metabolism , Primary Cell Culture , T-Lymphocytes/immunology , T-Lymphocytes/transplantation , Transplantation, Homologous/methodsABSTRACT
Antigen-specific immunotherapy of type 1 diabetes, typically via delivery of a single native ß cell antigen, has had little clinical benefit to date. With increasing evidence that diabetogenic T cells react against multiple ß cell antigens, including previously unappreciated neo-antigens that can be emulated by mimotopes, a shift from protein- to epitope-based therapy is warranted. To this end, we aimed to achieve efficient co-presentation of multiple major epitopes targeting both CD4+ and CD8+ diabetogenic T cells. We have compared native epitopes versus mimotopes as well as various targeting signals in an effort to optimize recognition by both types of T cells in vitro. Optimal engagement of all T cells was achieved with segregation of CD8 and CD4 epitopes, the latter containing mimotopes and driven by endosome-targeting signals, after delivery into either dendritic or stromal cells. The CD4+ T cell responses elicited by the endogenously delivered epitopes were comparable with high concentrations of soluble peptide and included functional regulatory T cells. This work has important implications for the improvement of antigen-specific therapies using an epitope-based approach to restore tolerance in type 1 diabetes and in a variety of other diseases requiring concomitant targeting of CD4+ and CD8+ T cells.
