Objective: To compare the activity difference of the high affinity humanized CD19 chimeric antigen receptor (CAR)-T cells and murine CD19 CAR-T cells. Methods: Peripheral venous blood T cells from 8 healthy volunteers were collected and infected with humanized and murine CD19 CAR lentivirus. Human and murine CD19 CAR-T cells were prepared and cell proliferation was detected by cell counting kit-8 (CCK-8) method. The cytotoxicity of CD3(+) T cells, humanized and murine CD19 CAR-T cells to NALM-6 cells was detected by lactate dehydrogenase assay. Thirty BAL B/c nude mice transplanted with NALM-6 cells were randomly divided into 3 groups with 10 mice in each group and injected humanized CD19 CAR-T cells, mouse CD19 CAR-T cells and control CD3(+) T cell via tail vein, respectively. The proportion of NALM-6 cells in peripheral blood and the proportion of CD19 CAR-T cells in T cells from the vein of the inner canthus were detected by flow cytometry. The overall survival of BAL B/c nude mice was observed. Results: The proliferation of mouse and humanized CD19 CAR-T cells were (68.50±0.93)% and (80.63±1.41)%, respectively (t=20.353, P<0.001) after cultured in vitro for 24 hours, and were (91.38±1.41)% and (148.13±1.25)%, respectively (t=85.364, P<0.001) after cultured for 48 hours. When the effect to target ratio was 1∶1, there was no difference between the humanized and murine CD19 CAR-T cell group after co-culture for 24 hours (P=0.169), while the killing activity of humanized CD19 CAR-T cells against NALM-6 cells was higher than that of murine CD19 CAR-T cells (P<0.01) after 48 hours of co-culture. When the effect to target ratio was 4∶1, the cytotoxicity of humanized CD19 CAR-T cells against NALM-6 cells was higher than that of murine CD19 CAR-T cells in co-culture for 24 and 48 hours (P<0.01). On the seventh day of CD19 CAR-T cell therapy, the proportion of NALM-6 cells in the peripheral blood of BAL B/c nude mice decreased to the lowest level in the humanized CD19 CAR-T cell group and the murine CD19 CAR-T cell group. After 21 days, the proportion of NALM-6 cells in the murine CD19 CAR-T cell group was higher than that in the humanized CD19 CAR-T cell group (P(21 d)=0.001, P(28 d)<0.001, P(35 d)<0.001). The proportion of humanized and murine CD19 CAR-T cells in the peripheral blood reached the peaks after 7 days of therapy, and the proportion of humanized CD19 CAR-T cells was higher than that of murine CAR-T cells (P(7 d)=0.002). The CD19 CAR-T cells disappeared in the peripheral blood in the murine CD19 CAR-T cell group after 14 days of therapy, while in the humanized CD19 CAR-T cell group it disappeared after 21 days of therapy. The median survival of BAL B/c nude mice in the murine CD19 CAR-T cell group and the humanized CD19 CAR-T cell group was 42 days and 63 days, respectively (χ(2)=15.382, P<0.001). Conclusions: High affinity humanized CD19 CAR-T cells have stronger proliferation, higher cytotoxicity and longer survival time compared with those of murine CD19 CAR-T cells. The results indicate that the clinical efficacy of humanized CD19 CAR-T cells would be better than that of murine CD19 CAR-T cells.
目的： 比较人源化CD19嵌合抗原受体(CAR)-T细胞与鼠源CD19 CAR-T细胞的功能。 方法： 收集8名健康志愿者的外周静脉血T细胞，行人源化和鼠源CD19 CAR慢病毒感染，制备人源化和鼠源CD19 CAR-T细胞，采用细胞计数8法检测细胞增殖情况。以急性淋巴细胞白血病Nalm-6细胞作为靶细胞，采用乳酸盐脱氢酶法检测对照CD3(+) T细胞、人源化及鼠源CD19 CAR-T细胞的细胞杀伤活性。将30只Nalm-6细胞荷瘤裸鼠采用随机区组法随机分为3组，每组10只，分别经尾静脉注射人源化CAR-T细胞、鼠源CAR-T细胞和对照CD3(+) T细胞悬液。采用流式细胞术检测内眦静脉血Nalm-6细胞占外周血细胞比例和CD19 CAR-T细胞占T细胞比例。观察裸鼠的生存时间。 结果： 体外培养24 h，鼠源和人源化CAR-T细胞的增殖率分别为(68.50±0.93)%和(80.63±1.41)%，差异有统计学意义(t＝20.353, P<0.001)；共培养48 h时，分别为(91.38±1.41)%和(148.13±1.25)%，差异亦有统计学意义(t＝85.364, P<0.001)。效靶比为1∶1时，共培养24 h，人源化CD19 CAR-T细胞组与鼠源CD19 CAR-T细胞组对Nalm-6细胞的杀伤活性差异无统计学意义(P＝0.169)；共培养48 h，人源化CD19 CAR-T细胞组对Nalm-6细胞的杀伤活性高于鼠源CD19 CAR-T细胞组(P<0.01)。效靶比为4∶1时，共培养24和48 h，人源化CD19 CAR-T细胞组对Nalm-6细胞的杀伤活性均高于鼠源CD19 CAR-T细胞组(均P<0.01)。CAR-T细胞治疗第7天，人源化CD19 CAR-T细胞组、鼠源CAR-T细胞组裸鼠外周血中Nalm-6细胞比例下降至最低；21 d后，鼠源CAR-T细胞组裸鼠体内Nalm-6细胞比例高于人源化CAR-T细胞组(P(21 d)＝0.001, P(28 d)<0.001, P(35 d)<0.001)。人源化CD19 CAR-T细胞组和鼠源CAR-T细胞组裸鼠外周血中CAR-T细胞比例均于CAR-T细胞治疗第7天达到峰值，人源化CD19 CAR-T细胞组高于鼠源CAR-T细胞组(P(7 d)＝0.002)。鼠源CAR-T细胞组裸鼠外周血中CAR-T细胞于第14天消失，人源化CAR-T细胞组裸鼠外周血中CAR-T细胞至第21天消失。鼠源CAR-T细胞组和人源化CD19 CAR-T细胞组裸鼠的中位生存时间分别为42和63 d，差异有统计学意义(χ(2)＝15.382，P<0.001)。 结论： 人源化CD19 CAR-T细胞比鼠源CD19 CAR-T细胞增殖能力强、对急性淋巴细胞白血病细胞的杀伤活性高、体内存留时间长，用于急性淋巴细胞白血病的临床疗效可能会优于鼠源CD19 CAR-T细胞。.
Keywords: Acute lymphoblastic leukemia; CAR-T cells; Cytotoxicity; Humanized; Murine.