| Co-Investigator(Kenkyū-buntansha) |
NAKAMORI Mikihito Wakayama Medical School, graduated student, 医学部・大学院
TERASAWA Hiroshi Wakayama Medical School, graduated student, 医学部・大学院
NISHIMOTO Norio Wakayama Medical School, Assistant, 医学部, 助手 (70244746)
TAMAI Mikiko Wakayama Medical School, Assistant, 医学部, 助手 (40260814)
SHONO Yoshiharu Wakayama Medical School, Assistant, 医学部, 助手 (60264884)
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| Research Abstract |
In this study, we transduced melanoma tumor-infiltrating lymphocytes (TILs) with the IL-2 gene and darified functional characteristics of the TIL transductants. TILs transduced with 3'-end-truncated IL-2 gene (480bp) produced high amounts of IL-2 detected in supematants when compared to TILs transduced with the naive IL-2 gene containing 3'-end adenine-thymidine (AI)-rich sequences (650bp). The level of IL-2 in supematants was higher with the addition of anti-Tac antibody (Ab) to block the consumption of IL-2 by die TILs. These TILs could proliferate autonomously in the absence of exogenous IL-2, and the proliferation of TILs could be completely blocked by anti-IL-2 Ab or anti-IL-2 receptor Ab. Thus TILs transduced with IL-2 gene can proliferate through the autocrine loop. However, the expression of IL-2 from TILs transduced with the IL-2 gene was downregulated after 2 to 3 weeks of G418 selection. Our study indicates the feasibility of transduction and expression of a truncated 480-bp IL-2 gene into TILs and possiblhty of employing adoptive immunotherapy protocols using TILs modified with this IL-2 gene. Next, in a murine subcutaneus tumor model, we inoculated IL-2 gene-modified fibroblasts and/or tumor cells into syngeneic mice, and observed die tumor growth. The tumor growth was significantly inhibited in mice inoculated with parental tumor cells plus IL-2 gene-modified fibroblasts, compared with that in parental tumor cells alone. Moreover, we inoculated tumortissue to murine cecum orthotopically, and treated with IL-2 gene-modified fibroblasts plus tumor cells. The tumor volume in cecum was also significantly decreased. These results suggest that gene therapy using IL-2 gene-modified fibroblasts may be a promising strategy for a clinical application.
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