In vivo anti-lung cancer activity mediated by double-transfected effector cells in therapeutic xenografted mouse models.
(A) The amount of CCL2 produced by luciferase-transfected LK79 cells (LK79/luc) was similar to that produced by the parent LK79 cells. (B) Nine-week-old NOG mice (n = 18) inoculated into the abdominal wall with 5×106 LK79/luc cells were divided into 3 cohorts. On day 4, when each tumor mass had become palpable, three mice in each cohort started to receive weekly intravenous administration of 5×106 double-transfected effector cells (cohort iii; black circles), WT1-siTCR single-transfected effector cells (cohort ii; gray square), or CD8+ T cells simply activated using OKT-3/IL-2 as a negative control (cohort i; clear circles), the effector cells all being generated from an identical donor. Intravenous administration was performed three times in total, and the relative mass burden was serially monitored on the basis of luciferase photon counts relative to those on day 4, before the start of therapeutic infusion. Double-transfected effector cells in cohort iii mice most effectively suppressed the growth of LK79/luc cells, notably in the immediate phase after therapeutic infusion (on day 7). In contrast, WT1-siTCR single-transfected effector cells gradually suppressed the growth of LK79/luc cells, being apparently dependent on time and the total number of effector cells infused. Effector cells that had been simply activated also displayed a marginal degree of tumor suppression, probably because of xenoreactivity. Error bars represent SDs. NGM-CD8+ T cells indicate CD8+ T cells simply activated using OKT-3/IL-2, expressing neither CCR2 nor WT1-specific TCR. (C) Serial bioluminescence images of mice in each cohort are shown. On day 28, 10 days after the last therapeutic infusion, durable growth suppression of LK79/luc cells was most evident in cohort iii mice that had received double-transfected effector cells. NGM-CD8+ T cells represent CD8+ T cells simply activated using OKT-3/IL-2, expressing neither CCR2 nor WT1-specific TCR.