To this end, F331 tumor-bearing mice were injected with PBS, Reg-1 KO B7-H3-CAR T cells, Ctrl KO B7-H3-CAR T cells or Reg-1 KO SP6-CAR T cells, followed by flow cytometric analysis of single-cell suspensions from lungs on day 21 post-CAR T-cell infusion. Here, SP6 is linked to neoplasm.