CD2/CD3/CD28 STIMULATION INCREASES CYTOTOXICITY OF HUMAN INVARIANT NATURAL KILLER T CELLS AGAINST PH+ B-ACUTE LYMPHOBLASTIC LEUKEMIA
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1
St Jude Children's Research Hospital, Bone Marrow Transplantation and Cellular Therapy, United States
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2
St Jude Children's Research Hospital, Animal Imaging Center, United States
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3
St Jude Children's Research Hospital, Hartwell Center for Bioinformatics and Biotechnology, United States
Innate invariant natural killer T (iNKT) cells are regulatory and cytotoxic. Here we report mechanisms to augment these effector functions in human CD3+Vα24+ iNKT cells. PBMC were stimulated with alpha-galactosylceramide (α-GalCer) and human IL-2 and IL-7. CD3+Vα24+ cells were sorted to >98% purity (day 7), co-cultured with irradiated allogeneic PBMC feeders with IL-2 and IL-7, and resorted at day 21 for functional assays including Luminex® 26-plex array, mRNA profiling, BADTA® cytotoxicity, and in vivo Nalm6 leukemia xenograft clearance under different iNKT stimulation conditions. iNKT cells robustly expanded (mean day 21 yield 6.7x106±0.8x106 from 8.9x103 ± 0.6x103 day 0 iNKT) from n=49 total blood donor apheresis units. Day 21 anti-CD2/CD3/CD28-stimulated iNKT cells expressed significant IL-4, IL-5, IL-13, GM-CSF and IFN-γ by Luminex® and high levels of GranzymeB and FasL by FACS and mRNA profiling. Day 21 iNKT cells displayed cytotoxicity against Ph+ Nalm6 B-ALL but not K562 myeloblasts in BADTA® assays which augmented by iNKT activation with anti-CD2/CD3/CD28 (mean±SEM 60.8%±2.8) versus α-GalCer (11.5%±5.0), when compared to unstimulated day 21 iNKT cells (11.0%±4.1). Inhibition of GranzymeB with Z-AAD-CMK abrogated iNKT cytotoxicity against Nalm6 in vitro (16.5%±2.8). Infusion of anti-CD2/CD3/CD28 stimulated day 21 iNKT cells induced clearance of Nalm6 xenografts by bioluminescence imaging as compared to vehicle and unstimulated day 21-expanded iNKT-treated controls. These findings identify a novel mechanism to optimize cytotoxic effector function of expanded human iNKT cells for application in novel therapeutic strategies against high-risk B-ALL.
Keywords:
iNKT cells,
Cytotoxicity,
GranzymeB,
Apoptosis,
Necrosis,
B-ALL
Conference:
15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013.
Presentation Type:
Abstract
Topic:
Innate immunity
Citation:
Alves De Araujo
CA,
Calabrese
C,
Luszczek
W,
Neale
G,
Seth
A and
Pillai
A
(2013). CD2/CD3/CD28 STIMULATION INCREASES CYTOTOXICITY OF HUMAN INVARIANT NATURAL KILLER T CELLS AGAINST PH+ B-ACUTE LYMPHOBLASTIC LEUKEMIA.
Front. Immunol.
Conference Abstract:
15th International Congress of Immunology (ICI).
doi: 10.3389/conf.fimmu.2013.02.00903
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Received:
26 Jun 2013;
Published Online:
22 Aug 2013.
*
Correspondence:
Dr. Asha Pillai, St Jude Children's Research Hospital, Bone Marrow Transplantation and Cellular Therapy, Memphis, TN, 38105, United States, asha.pillai@stjude.org