IL-21-treated naive CD45RA+ CD8+ T cells represent a reliable source for producing leukemia-reactive cytotoxic T lymphocytes with high proliferative potential and early differentiation phenotype.
Clinical tumor remissions after adoptive T-cell therapy are frequently not durable due to limited survival and homing of transfused tumor-reactive T cells, what can be mainly attributed to the long-term culture necessary for in vitro expansion. Here, we introduce an approach allowing the reliable in vitro generation of leukemia-reactive cytotoxic T lymphocytes (CTLs) from naive CD8+ T cells of healthy donors, leading to high cell numbers within a relatively short culture period. The protocol includes the stimulation of purified CD45RA+ CD8+ T cells with primary acute myeloid leukemia blasts of patient origin in HLA-class I-matched allogeneic mixed lymphocyte-leukemia cultures. The procedure allowed the isolation of a large diversity of HLA-A/-B/-C-restricted leukemia-reactive CTL clones and oligoclonal lines. CTLs showed reactivity to either leukemia blasts exclusively, or to leukemia blasts as well as patient-derived B lymphoblastoid-cell lines (LCLs). In contrast, LCLs of donor origin were not lysed. This reactivity pattern suggested that CTLs recognized leukemia-associated antigens or hematopoietic minor histocompatibility antigens. Consistent with this hypothesis, most CTLs did not react with patient-derived fibroblasts. The efficiency of the protocol could be further increased by addition of interleukin-21 during primary in vitro stimulation. Most importantly, leukemia-reactive CTLs retained the expression of early T-cell differentiation markers CD27, CD28, CD62L and CD127 for several weeks during culture. The effective in vitro expansion of leukemia-reactive CD8+ CTLs from naive CD45RA+ precursors of healthy donors can accelerate the molecular definition of candidate leukemia antigens and might be of potential use for the development of adoptive CTL therapy in leukemia.
Department of Medicine III, Hematology and Oncology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, Mainz, Germany.
Jana
J
Albrecht
Michaela
M
Frey
Daniel
D
Teschner
Alexander
A
Carbol
Matthias
M
Theobald
Wolfgang
W
Herr
Eva
E
Distler
D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D005434:Flow Cytometry; D006801:Humans; D007378:Interleukins / Q000276:immunology*; D015470:Leukemia, Myeloid, Acute / Q000276:immunology*; D017493:Leukocyte Common Antigens / Q000276:immunology*; D010641:Phenotype; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000276:immunology*; D000098546:Interleukin-21
D007378:Interleukins; D017493:Leukocyte Common Antigens; D000098546:Interleukin-21