Nalm6 cells

Human pre–B cell leukemic line NALM-6 cells (ATCC) were cultured in T cell medium (RPMI plus 10% FBS) and used as CD19⁺ target cells. The HBL-1 DLBCL cell line expressing CD58 was prepared as described previously (35 (link)). Parental HBL-1 and HBL-1–CD58⁺ were cultured in IMDM plus 10% FBS.

6- to 10-week-old NSG mice were obtained from Jackson Laboratory (Bar Harbor, ME) or bred in-house under an approved institutional animal care and use committee protocol and maintained under pathogen-free conditions. Animals were injected via tail vein with 1 million viable NALM6 cells (ATCC CRL-3273) engineered to express click beetle green (CBG) luciferase. 8 days after injection of leukemic cells, mice received 10 million T cells via tail vein injections. Mice were monitored weekly using bioluminescent imaging to determine the presence of tumor using the Xenogen Spectrum (Caliper Life Sciences, Hopkinton, MA) imaging system using Living Image v4.2 software, as previously described.³⁹ (link) Peripheral blood was obtained by retro-orbital bleeding, and blood was examined for evidence of leukemia and T cell engraftment by flow cytometry using BD Trucount (BD Biosciences, Cat #340334) tubes as previously described.⁵² (link)

B-ALL cell lines were maintained in RPMI (Gibco) supplemented with 10% FBS, penicillin/streptomycin, and GlutaMAX (Gibco) at 37 °C under humidified 5% CO₂ condition. REH cells were a gift from the Parekh lab at Children’s Hospital Los Angeles (CHLA). Nalm6 cells were a gift from the Kim lab at CHLA. KPON-8 cells were a gift from the Chen lab at City of Hope. REH cells can be purchased from ATCC (cat. no. CRL-8286, RRID:CVCL_1650). Nalm6 cells can be purchased from ATCC (cat. no. CRL-3273, RRID:CVCL_UJ05). KOPN-8 cells can be purchased from DSMZ (cat. no. ACC-552, RRID:CVCL_1866).

HEK293T cells were obtained from DSMZ. They were cultured in DMEM (Life Technologies) with 10% fetal bovine serum (Life Technologies) and 1% l-glutamine (Life Technologies). NALM-6 cells were obtained from ATCC and cultured in RPMI medium with the same additives as for HEK293T cells. All cells were kept at 37 °C in a humidified incubator containing 5% CO₂. They were routinely tested for mycoplasma infection. Viably-cryopreserved cells from a patient-derived xenograft model of human B-ALL harboring a TCF3-HLF fusion (ALL1807) were established as previously described [17 (link)] and used for downstream sequencing studies.

Prior to transfection, HEK 293T (ATCC CRL-3216) cells were cultured in high glucose Dulbecco's modified Eagle's medium (DMEM; Gibco), supplemented with 10% fetal bovine serum (FBS) (BioChrom), 1% l-glutamine and 1% of Pen/Strep (10,000 units/mL penicillin and 10,000 µg/mL streptomycin). Prior to transduction, NALM-6 cells (ATCC CRL-3273) were cultured in RPMI 1640 (Gibco) media supplemented with 10% FBS, 1% l-glutamine and 1% 1X-Pen/Strep. All cells were incubated at 37 °C at 5% CO₂.