Journal: Journal of translational medicine

Article Title: Unraveling resistance mechanisms in anti-CD19 chimeric antigen receptor-T therapy for B-ALL: a novel in vitro model and insights into target antigen dynamics.

doi: 10.1186/s12967-024-05254-z

Figure Lengend Snippet: Fig. 1 Proliferation and specific cytotoxic effects of CART-19 cells. A The design of the CAR-T cell construction experiments. B Morphological images of activated T cells clustered after 24 h and 72 h of incubation with TransAct CD3/28 beads. C Flow cytometric analysis of CAR expression on the surface of mock T, and CART-19 cells with biotin-conjugated anti-Fab antibody followed by PE-conjugated streptavidin. Gating was based on the same cells stained with isotype-matched antibody. The median fluorescence intensity (MFI) was calculated for CAR-T population in the PE fluorescence channel (right column). This result is the representative of three separate experiments using cells from healthy volunteer donors. D The phenotypic characterization of CART-19 cells by flow cytometry. The ratio of CD4+ / CD8+ T cells (left) and the proportion of TN/CM (right) are shown. E Growth curves of CAR-T cells. Data represent the mean ± s.d. of three separate experiments. F Cytolytic activities of CART-19 cells in cell assays. Nalm-6 cells were labeled with CFSE labeling reagent (Sigma-Aldrich, USA) and co-cultured with CART-19 cells at the E: T ratio of 1:1 for 30 h. The presence of CFSE-labeled cells was observed by mi croscopy. Bar, 100 μm. G Cytotoxic activity of mock NT and CART cells against Nalm-6 cells. The effector cells were co-cultured with target cells at E: T ratios of 1:5, 1:2, 1:1 and 5:1 with a total cell number of 1 × 106. H Dynamic changes of cytokine secretion profile of CART-19 cells during 24 h after co-culture with Nalm-6 cells at E: T ratios of 1:5 to 5:1. Data were visualized by heatmap. Concentrations (pg/ml) of cytokines and chemokines in the supernatant were detected by multiplex immunoassay and the values were log2 transformed

Article Snippet: To evaluate CAR expression after 7–10 days of culture, CART-19 cells were washed once and incubated with goat anti-human biotin conjugated anti-Fab antibody (Jackson ImmunoResearch, USA) for 30 min at room temperature.

Techniques: Incubation, Expressing, Staining, Fluorescence, Flow Cytometry, Labeling, Cell Culture, Activity Assay, Co-Culture Assay, Multiplex Assay, Transformation Assay

Journal: Journal of translational medicine

Article Title: Unraveling resistance mechanisms in anti-CD19 chimeric antigen receptor-T therapy for B-ALL: a novel in vitro model and insights into target antigen dynamics.

doi: 10.1186/s12967-024-05254-z

Figure Lengend Snippet: Fig. 5 Observation of CD19-BBζ-CAR expression in relapsed Nalm-6 cells and salvage treatment. A Detection of FMC63 and CD247 transcripts and 4-1BB gene of CAR in CD19+ Nalm-6 (red) and relapsed CD19− Nalm-6 cells (blue) by qRT-PCR. Data of left bar graph represent the relative quantification using ACTB as the internal reference. Error bars represent s.d. The data are the representative of three independent experiments. B Expression of CD19 and CAR on CD19+ Nalm-6 cells and relapsed CD19− Nalm-6 cells analyzed by flow cytometry (representative of 3 experiments). Merge Graphs, the blue dots represent CD19− Nalm-6 cells and the red dots represent Nalm-6 cells. C Confocal imaging of Nalm-6 cells and relapsed CD19− Nalm-6 cells using Alexa Flour 488-conjugated anti-CD19 antibody (green), Alexa Flour 647-conjugated anti-CAR19 antibody (red), and DAPI (blue). D Lentiviral integration sites of CAR transduced Nalm-6 cells were analyzed by linear-amplification mediated PCR (LAM-PCR) and visualized with Circos plots. The integration sites across the genome and genomic features were shown from outer to inner circle: (1) cytogenetic bands; (2) genes that harbor these integration sites along with a bar chart showing the reads of integration sites; (3) the distribution of integration sites, with colored circles representing different gene functional regions of the host sequence: purple for promoter region, green for intron region, and red for distal intergenic region. E Phenotype changes of Nalm-6 cells transduced with small amount of CD19 CAR lentiviruses detected by flow cytometry over time. Gating was based on the same cells stained with isotype-matched antibody. F Dynamics of CD19− B phenotype in relapsed cells after co-culture with different ratios (5×, 20×) of Nalm-6 cells. Gating was based on the same cells stained with isotype-matched antibody. G Relapsed CD19− Nalm-6 cells were tested by qPCR specific for VSV-G sequence. H Comparison of in vitro efficacy of CD19-, CD22-, CD19/CD22- and CD22×CD19- CAR T cells. Cocultures with the relapsed cells were performed at 1:5, 1:1, and 5:1 E: T ratios, and lysis efficacies were detected by the LDH release assay Declarations

Article Snippet: To evaluate CAR expression after 7–10 days of culture, CART-19 cells were washed once and incubated with goat anti-human biotin conjugated anti-Fab antibody (Jackson ImmunoResearch, USA) for 30 min at room temperature.

Techniques: Expressing, Quantitative RT-PCR, Quantitative Proteomics, Flow Cytometry, Imaging, Amplification, Functional Assay, Sequencing, Transduction, Staining, Co-Culture Assay, Comparison, In Vitro, Lysis, Lactate Dehydrogenase Assay