title: B7.1 immunogene therapy effectively activates CD(4+) tumor-infiltrating lymphocytes in the central nervous system in comparison with B7.2 gene therapy.
abstract: The B7 gene utilizing immunogene therapy is one of the most common methods against tumor growth. However, there is no known study that investigated the difference between B7.1 and B7.2 with regard to B7 gene therapy in the central nervous system (CNS). Therefore, to clarify the difference, we established B7.1 or B7.2 gene transduced tumor cells originating from the murine T cell lymphoma cell line EL4 (EL4-B7.1 or EL4-B7.2). First, we observed the survival time after intracranial inoculation of parent (IC-wt) or genetically modified tumor cells. All mice in control groups (IC-wt or IC-mock) were dead within 16 days. While there was significant survival elongation in the B7.2 modified group (IC-B7.2, p=0.0002), all mice in this group were dead of tumor growth within 22 days. On the other hand, 60% of mice inoculated with EL4-B7.1 (IC-B7.1) survived more than 120 days (p<0.0001). Second, to shed light on the anti-tumor immune response in situ, we tried to analyze CD(4+) tumor-infiltrating T lymphocytes (CD(4+) TIL). To purify and analyze CD(4+) TIL, we had to deplete F4/80(+) microglia because of the CD4 expression. In terms of activation marker expression in CD(4+) TIL, a small population was activated (CD25, 9.8%; CD69, 15.8%) in the control group (IC-wt). In contrast, the activation marker positive CD4+ TIL percentage both in IC-B7.1 (CD25, 25.1%; CD69, 40.1%) and IC-B7.2 (CD25, 16.2%; CD69, 28.3%) appeared to reflect the survival curve in both groups. These findings strongly suggest that, in the CNS, B7.1 gene therapy could effectively introduce CD(4+) TIL activation compared with B7.2 gene therapy. This is the first study clearly describing the difference between B7.1 gene therapy and B7.2 gene therapy in the CNS in terms of the activation status of CD(4+) TIL in situ.
authors.affiliation: Department of Neurosurgery, Gifu University School of Medicine, Gifu 500-8705, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Ando
authors.forename: Masanao
authors.initials: M
authors.lastname: Saio
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Ohe
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Tamakawa
authors.forename: Hai
authors.initials: H
authors.lastname: Yu
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakayama
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Yoshimura
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kaku
authors.forename: Toru
authors.initials: T
authors.lastname: Iwama
authors.forename: Jun
authors.initials: J
authors.lastname: Shinoda
authors.forename: Noboru
authors.initials: N
authors.lastname: Sakai
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takami
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics*; D018122:B7-1 Antigen / Q000235:genetics*; D051940:B7-2 Antigen; D001932:Brain Neoplasms / Q000276:immunology / Q000628:therapy*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D005434:Flow Cytometry; D015316:Genetic Therapy; D008213:Lymphocyte Activation; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D016399:Lymphoma, T-Cell / Q000276:immunology / Q000628:therapy*; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation; D016133:Polymerase Chain Reaction; D012313:RNA / Q000378:metabolism; D015996:Survival Rate; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497965:Cd86 protein, mouse; D017931:DNA Primers; D008562:Membrane Glycoproteins; D012313:RNA