脳内移植C−6グリオーマ細胞の着床，増殖におよぼす宿主免疫能と液性因子について

THE CORRELATION OF HOST-IMMUNOCOMPETENCE AND HOST-HUMORAL STATES TO THE TAKE INCIDENCE AND PROLIFERATIVE ACTIVITY OF IMPLANTATION C-6 GLIOMA CELLS

　抄録　最近腫瘍細胞の増殖機構に成長ホルモン依存性成長因子が関与すると言われている。又腫瘍細胞の着床と増殖に宿主免疫能と液性因子が影響を与えるとも言われるのでこの関連性の解明を目的とした。我々は2種の免疫不全マウス，即ち先天性胸腺欠損ヌードマウスと先天性下垂体性侏儒マウス（Snell dwarfmouse）を使用した。両者の相違はヌードマウスがホルモン的に全く正常であるが，dwarf mouseは下垂体前葉低形成によりGH,TSH,prolactinを欠損している。C−6グリオーマ細胞を皮下と脳内へ移植し（1×10⁵〜10⁶個）着床と増殖状態を比較した。ヌードマウスの着床・増殖はほぼ100％で8週頃で腫瘍死する。dwarf mouseは2週目まで明らかに皮下，脳内で着床をみたが以降消褪した。GH回復実験では（10μg／g連日皮下投与）腫瘍細胞は消褪せず増殖を示した。GHは脳内に入らないことが知られており，成長因子が腫瘍細胞の増殖に重要な役割をはたしたことが判明した。

Recently it has become evident that "second growth factor" of growth hormone (GH), such as somatomedines, has an effect on the prolife-ration and growth of tumor cells derived from nervous tissue. Effects of host-immunocompetence and the host-humoral states on the take incidence and proliferative activity of brain tumor cells were studied using two animal modeld : nude mouse and pituitary Snell dwarf mouse. Nude mouse is known to be immumodeficient. Pitui-tary Snell dwarf mouse is characterized by lack of circulating GH, TSH, prolactine, in addition to immunodeficiency. Cell line used in this expe-riment was C-6 cell of rat glioma cell. After intracranial implantation of C-6 glioma cells in the animals, the take incidence and growth rate of C-6 glioma cells were followed up and mea-sured over a period of 2 months. Tissues of implants were studied immunohistochemically and biochemically. Regardless of cell line, successful take incidence in the different animal species was found to be greater in the desending order of nude mouse, dwarf mouse. This confirmed the role of immunostates for the successful take of iso-, or heterologous tumor cells after implantation.We are now investigating the effect of exogenous GH on the growth rate of cells implanted in the dwarf mouse. This may clarify the effect ofgrowth factors on proliferative activity of im-planted tumor cells.