Fig. 6: Three-time injections of BBIR-T cells improved the cardiac function of MI mice.

a Schematic diagram of the number of BBIR-T-cell injections. Pdgfra-CRE:tdTomato mice were intramyocardially injected with biotinylated anti-CD248 F(ab’)2 immediately after MI surgery to label the F-Act. A total of 10⁶ BBIR-T cells were injected into the tail vein every three days beginning 14 days after MI. Mouse hearts were obtained for flow cytometry detection three days after BBIR-T cells injection. Created in BioRender. Haiting, C. (2025) https://BioRender.com/m61n139. b Flow cytometry of fibroblasts isolated from hearts of C57BL/6J WT and Pdgfra-CRE:tdTomato mice. Total cardiac fibroblasts were lineage traced by pdgfrα. F-Act was marked with antibodies against CD248-AF647. Quantifying the pdgfrα⁺ fibroblast ratio in live cells and the CD248⁺ cell ratio in pdgfrα⁺ fibroblasts. n = 5 mice at each group. Data are mean ± SEM and p-values are displayed in the bar charts, two-way ANOVA followed by Šídák multiple comparison test, one-way ANOVA followed by Tukey’s multiple comparison test. c, d Schematic diagram of the animal experiments. Mice were divided into 6 groups: sham, MI + BF, MI + BF + Activated T, MI + BBIR-T, MI + BF + BBIR-T, and MI + BF + anti-CD19 CAR-T. Each group underwent echocardiographic detection before, at 7, 14, and 28 days after MI surgery. The sham group only underwent chest opening without ligating the LAD; the remaining 5 groups underwent LAD ligation. Except for the sham and MI + BBIR groups, the other groups were injected intramyocardially with BF immediately after MI. On the 14th, 17th, and 20th days post-MI, except for the sham and MI + BBIR groups, the other groups were injected intravenously with different effector cells. All mice were tested for LV catheterization 28 days after MI and sacrificed for subsequent experiments. Created in BioRender. Haiting, C. (2025) https://BioRender.com/y36t712. e Typical short-axis M-type echocardiographic images in each group of mice 28 days after MI. The LVEF, LVFS, and LVAW thickness were quantified at different time points. The number of surviving mice (n) for each treatment group at each time point was displayed at the bottom of the bar chart. Data are mean ± SEM and p-values less than 0.05 are displayed in the bar chars, two-way ANOVA followed by Tukey’s multiple comparisons tests. f Typical LVP image of each group of mice detected by LV catheterization. The LVP, LVEDP, LV dP/dt maximum, and LV -dP/dt minimum were quantified. The number of mice (n) for each treatment group was displayed at the bottom of the bar chart. Data are mean ± SEM and p-values are displayed in the bar charts, one-way ANOVA followed by Tukey’s multiple comparison test. Source data are provided as a Source Data file.