Switch-mediated activation and retargeting of CAR-T cells for B-cell malignancies.

Abstract

Chimeric antigen receptor T (CAR-T) cell therapy has produced impressive results in clinical trials for B-cell malignancies. However, safety concerns related to the inability to control CAR-T cells once infused into the patient remain a significant challenge. Here we report the engineering of recombinant antibody-based bifunctional switches that consist of a tumor antigen-specific Fab molecule engrafted with a peptide neo-epitope, which is bound exclusively by a peptide-specific switchable CAR-T cell (sCAR-T). The switch redirects the activity of the bio-orthogonal sCAR-T cells through the selective formation of immunological synapses, in which the sCAR-T cell, switch, and target cell interact in a structurally defined and temporally controlled manner. Optimized switches specific for CD19 controlled the activity, tissue-homing, cytokine release, and phenotype of sCAR-T cells in a dose-titratable manner in a Nalm-6 xenograft rodent model of B-cell leukemia. The sCAR-T-cell dosing regimen could be tuned to provide efficacy comparable to the corresponding conventional CART-19, but with lower cytokine levels, thereby offering a method of mitigating cytokine release syndrome in clinical translation. Furthermore, we demonstrate that this methodology is readily adaptable to targeting CD20 on cancer cells using the same sCAR-T cell, suggesting that this approach may be broadly applicable to heterogeneous and resistant tumor populations, as well as other liquid and solid tumor antigens.

• Authors: David T Rodgers, Magdalena Mazagova, Eric N Hampton, Yu Cao, Nitya S Ramadoss, Ian R Hardy, Andrew Schulman, Juanjuan Du, Feng Wang, Oded Singer, Jennifer Ma, Vanessa Nunez, Jiayin Shen, Ashley K Woods, Timothy M Wright, Peter G Schultz, Chan Hyuk Kim, Travis S Young
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 113 Issue 4 Pg. E459-68 (Jan 26 2016) ISSN: 1091-6490 [Electronic] United States
• PMID: 26759369 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Antigens, CD19
• Antigens, Neoplasm
• Azides
• Basic-Leucine Zipper Transcription Factors
• CD22 protein, human
• Cytokines
• GCN4 protein, S cerevisiae
• Receptors, Antigen, T-Cell
• Recombinant Fusion Proteins
• Saccharomyces cerevisiae Proteins
• Sialic Acid Binding Ig-like Lectin 2
• Single-Chain Antibodies
• 4-azidophenylalanine
• Phenylalanine

Topics

• Animals
• Antigens, CD19 (immunology)
• Antigens, Neoplasm (immunology)
• Azides
• B-Lymphocytes (immunology, pathology)
• Basic-Leucine Zipper Transcription Factors (immunology)
• Cell Line, Tumor
• Cytokines (metabolism)
• Cytotoxicity, Immunologic
• Dose-Response Relationship, Immunologic
• Female
• Genes, Reporter
• Genetic Vectors
• Humans
• Immunotherapy, Adoptive (adverse effects, methods)
• Leukemia, B-Cell (therapy)
• Lymphocyte Activation
• Lymphopenia (etiology, prevention & control)
• Mice
• Mice, Inbred C57BL
• Mice, Inbred NOD
• Mice, SCID
• Phenylalanine (analogs & derivatives)
• Protein Engineering (methods)
• Receptors, Antigen, T-Cell (genetics, immunology)
• Recombinant Fusion Proteins (immunology)
• Saccharomyces cerevisiae Proteins (immunology)
• Sialic Acid Binding Ig-like Lectin 2 (immunology)
• Single-Chain Antibodies (genetics, immunology)
• Structure-Activity Relationship
• T-Cell Antigen Receptor Specificity
• T-Lymphocyte Subsets (immunology, transplantation)
• Xenograft Model Antitumor Assays