CD34-based enrichment of genetically engineered human T cells for clinical use results in dramatically enhanced tumor targeting.
Objective clinical responses can be achieved in melanoma patients by infusion of T cell receptor (TCR) gene transduced T cells. Although promising, the therapy is still largely ineffective, as most patients did not benefit from treatment. That only a minority of the infused T cells were genetically modified and that these were extensively expanded ex vivo may have prevented their efficacy. We developed novel and generally applicable retroviral vectors that allow rapid and efficient selection of T cells transduced with human TCRs. These vectors encode two TCR chains and a truncated CD34 molecule (CD34t) in a single mRNA transcript. Transduced T cells were characterized and the effects of CD34-based enrichment of redirected T cells were evaluated. Both CD8(+) and CD4(+) T cells could be transduced and efficiently co-expressed all introduced transgenes on their surface. Importantly, more than fivefold enrichment of both the frequency of transduced cells and the specific anti-tumor reactivity of the effector population could be achieved by magnetic beads-based enrichment procedures readily available for clinical grade hematopoietic stem cell isolation. This CD34-based enrichment technology will improve the feasibility of adoptive transfer of clinically relevant effectors. In addition to their enhanced tumor recognition, the enriched redirected T cells may also show superior reactivity and persistence in vivo due to the high purity of transduced cells and the shortened ex vivo culture.
Norell
Håkan
H
Division of General Surgery, Department of Surgery, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA. norell@musc.edu
Zhang
Yi
Y
McCracken
James
J
Martins da Palma
Telma
T
Lesher
Aaron
A
Liu
Yueying
Y
Roszkowski
Jeffrey J
JJ
Temple
Anquanette
A
Callender
Glenda G
GG
Clay
Timothy
T
Orentas
Rimas
R
Guevara-Patiño
José
J
Nishimura
Michael I
MI
D018952:Antigens, CD34 / Q000235:genetics / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000637:transplantation; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000637:transplantation; D019496:Cancer Vaccines; D019672:Genes, T-Cell Receptor / Q000235:genetics; D005818:Genetic Engineering; D006801:Humans; D018189:Immunomagnetic Separation; D016219:Immunotherapy, Adoptive; D008545:Melanoma / Q000235:genetics / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012190:Retroviridae; D017384:Sequence Deletion; D014161:Transduction, Genetic
D018952:Antigens, CD34; D019496:Cancer Vaccines; D011993:Recombinant Fusion Proteins