Fig. 4

In vivo CAR T cell monitoring method for xenograft tumor murine models. A Schematic workflow summarizing the xenografting of MM1S or Monomac-6 tumor cell lines (day 0) one day after mouse irradiation (2.5 Gy). On day 1, CS1 or IL-1RAP CAR T cells were intravenously injected. Biological samples were harvested kinetically (PB, day 2 to day 30 or 50) or at the end of the experiment (organs, day 30, Monomac-6/IL-1RAP) and processed for gDNA extraction and ddPCR. For the MM1S/CS1 model, mice were challenged again with tumor cells; n = 3 mice (12 in total) were included in each group. B Individual early (day 0 to day 50) longitudinal monitoring of CS1 and IL-1RAP monitoring with 28z and 28BBz ddPCR, respectively. Green and blue curves represent ddPCR CAR T cell monitoring for mice grafted or not with the target tumors, respectively. The mean CAR transgene copy number detected in each group is plotted (n = 3 mice/group). Arrows show the second CAR T cell expansion peaks following the second tumor injection. AUC: area under the curve day 0 to 28, calculated with GraphPad software. C Monitoring CAR T cells in organs. Transgene copies/µg of DNA obtained by 28BBz ddPCR on gDNA extracted from organs of n = 3 individual mice receiving IL-1RAP CAR T cells after grafting (green) or not (blue) of Monomac6 tumor cells. Each quantification was performed in duplicate. (−) and (+) are negative and positive PCR controls as respectively no template or IL-1RAP CAR+ cell line DNA