Tonic Signaling and Its Effects on Lymphopoiesis of CAR-Armed Hematopoietic Stem and Progenitor Cells

• Published in: The Journal of immunology (1950) Vol. 202; no. 6; pp. 1735 - 1746
• Main Authors: Albert, Susann, Koristka, Stefanie, Gerbaulet, Alexander, Cartellieri, Marc, Arndt, Claudia, Feldmann, Anja, Berndt, Nicole, Loureiro, Liliana R, von Bonin, Malte, Ehninger, Gerhard, Eugster, Anne, Bonifacio, Ezio, Bornhäuser, Martin, Bachmann, Michael P, Ehninger, Armin
• Format: Journal Article
• Language: English
• Published: United States 15.03.2019
• Subjects: Adoptive Transfer; Animals; Cell Differentiation - physiology; Hematopoietic Stem Cell Transplantation - methods; Hematopoietic Stem Cells - metabolism; Humans; Lymphocyte Activation - physiology; Lymphopoiesis - physiology; Mice; Mice, Inbred C57BL; Receptors, Chimeric Antigen - metabolism; Signal Transduction - physiology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.1801004

Long-term survival of adoptively transferred chimeric Ag receptor (CAR) T cells is often limited. Transplantation of hematopoietic stem cells (HSCs) transduced to express CARs could help to overcome this problem as CAR-armed HSCs can continuously deliver CAR multicell lineages (e.g., T cells, NK cells). In dependence on the CAR construct, a variable extent of tonic signaling in CAR T cells was reported; thus, effects of CAR-mediated tonic signaling on the hematopoiesis of CAR-armed HSCs is unclear. To assess the effects of tonic signaling, two CAR constructs were established and analyzed 1) a signaling CAR inducing a solid Ag-independent tonic signaling termed CAR-28/ζ and 2) a nonstimulating control CAR construct lacking intracellular signaling domains termed CAR-Stop. Bone marrow cells from immunocompetent mice were isolated, purified for HSC-containing Lin cKit cells or the Lin cKit Sca-1 subpopulation (Lin Sca-1 cKit ), and transduced with both CAR constructs. Subsequently, modified bone marrow cells were transferred into irradiated mice, in which they successfully engrafted and differentiated into hematopoietic progenitors. HSCs expressing the CAR-Stop sustained normal hematopoiesis. In contrast, expression of the CAR-28/ζ led to elimination of mature CAR T and B cells, suggesting that the CAR-mediated tonic signaling mimics autorecognition via the newly recombined immune receptors in the developing lymphocytes.