S－180瘤苗联用BCG治疗效应的研究

本文观察荷瘤小鼠（接种１×１０５Ｓ－１８０瘤细胞）用异体同基因Ｓ－１８０瘤苗联用ＢＣＧ治疗的主动免疫试验的效应．结果表明，９０％（１８／２０）实验鼠产生迟发型皮肤赵敏反应，与对照组或单一治疗组（ＢＣＧ组、瘤苗组）相比，其生存期明显延长（Ｐ＜０．０５）和转移瘤肺结节数显著下降（Ｐ＜０．０１）．ＤＣＨ反应持久的四只小鼠显示了强的抗癌免疫反应．结果证实，采用Ｈａｎｎａ免疫方案可以提高接种１×１０５瘤细胞的荷瘤鼠抗病免疫反应，并可借ＤＣＨ皮试反应监测其ＡＳＩ疗效。     

牛膝多糖抗肿瘤作用及免疫机制实验研究

作者研究了牛膝多糖（ＡＢＰ）对Ｓ＿（１８０）荷瘤小鼠的抑瘤作用和脾细胞诱生ＴＮＦ和ＬＡＫ细胞活性的影响。结果证实ＡＢＰ２５～１００ｍｇ·Ｋｇ￣（－１）·ｄ￣（－１）×７的抑瘤率为３１％～４０％。环磷酰胺１２．５ｍｇ／ｋｇ单次的抑瘤率为１７％，与ＡＢＰ１００ｍｇ·ｋｇ￣（－１）·ｄ￣（－１）合用的抑瘤率为５８％，有明显协同作用。ＡＢＰ１～２μｇ／ｍｌ对小鼠肉瘤Ｓ＿（１８０）细胞和人白血病Ｋ＿（５６２）细胞的增殖均有明显抑制作用，ＡＢＰ５０及１００ｍｇ／ｋｇ腹腔注射能明显提高Ｓ＿（１８０）荷瘤小鼠ＬＡＫ细胞活性和ＴＮＦ－β生成。诱生ＴＮＦ的达峰时间是２次腹腔注射后的第８天。为探讨其抗肿瘤机理，对Ｓ＿（１８０）细胞膜成份进行了分析，结果显示ＡＢＰ与细胞接触２４小时，引起细胞膜唾液酸含量升高，膜磷脂含量降低，这些变化差异均有显著性意义（Ｐ＜０．０５或Ｐ＜０．０１）；但膜胆固醇含量、膜流动性（Ｃ／Ｐ比值）不受影响。提示ＡＢＰ的抗瘤机理与其增强宿主免疫功能及改变细胞膜生化特性有关。     

大豆皂甙对小鼠移植肿瘤生长的影响

目的探讨大豆皂甙（ＴＳ）对肿瘤细胞生长的影响及其机制。方法采用Ｃ５７ＢＬ／６小鼠皮下接种Ｓ１８０细胞后，经口连续７天注入胃内０（对照组）、１０、２０和４０ｍｇ／ｋｇＴＳ。结果第８天注入上述剂量ＳＴ组小鼠移植肿瘤平均重量分别为１．１８、０．８和０．８９ｇ，均较对照组２．２３ｇ明显减轻（Ｐ＜０．０５～０．０１）。小鼠腹腔注入Ｓ１８０细胞后，连续７天经腹腔分别注入上述剂量ＴＳ，第８天各组小鼠Ｓ１８０细胞周期进程均延缓，Ｇ０／Ｇ１期Ｓ１８０细胞平均百分数分别为３０．７６、４１．７４和３４．８４，均较对照组２４．７６增多，４０ｍｇ／ｋｇ组小鼠最明显（Ｐ＜０．０５）；Ｓ期Ｓ１８０细胞分别为１５．２８、１１．６４和１１．８０，均较对照组３０．３０明显减少（Ｐ＜０．０５）。结论ＴＳ对小鼠移植肿瘤生长有抑制作用，可能与肿瘤细胞从Ｇ０／Ｇ１期向Ｓ期进程受阻有关。     

白细胞介素—12基因与HSV—TK基因联合治疗小鼠肝癌的研究

目的　观察白介素１２（ＩＬ１２） 基因与单纯疱疹病毒胸苷激酶（ＨＳＶＴＫ） 基因联合治疗小鼠肝癌的疗效。方法　将ＩＬ１２ 基因和ＨＳＶＴＫ 基因分别转导入小鼠肝癌ＭＭ４５Ｔ－Ｌｉ 细胞,获稳定表达的ＭＭ４５Ｔ－ＬｉＩＬ１２ 和ＭＭ４５Ｔ－ＬｉＴＫ。于Ｂａｌｂｃ 小鼠皮下接种ＭＭ４５Ｔ－Ｌｉ 细胞２ ×１０５ ,待肿瘤长至０－５～１－０ ｃｍ 时,将ＭＭ４５Ｔ．ＬｉＴＫ细胞与经６０ Ｃｏ 照射的ＭＭ４５Ｔ．ＬｉＩＬ１２ 细胞混合,行瘤内注射治疗,于治疗次日,腹腔注射Ｇａｎｃｉｃｌｏｖｉｒ（ＧＣＶ４０ ｍｇ·ｋｇ－ １·ｄ－ １） ,连续注射１０ 天。按同样方法观察对远侧接种的肿瘤的治疗作用,并通过细胞毒Ｔ淋巴细胞（ＣＴＬ） 活性检测及免疫组化染色,探讨其抗肿瘤机制。结果　ＭＭ４５Ｔ．ＬｉＩＬ１２ 与ＨＳＶＴＫＧＣＶ 联合治疗,肿瘤体积显著缩小,生长受到抑制,疗效显著优于单独治疗组（ Ｐ＜ ０．０１） 。有６０％ 小鼠的肿瘤完全消退,且观察２ 个月无肿瘤生长。两者联合治疗,对远侧肿瘤也具有明显的抗肿瘤作用（ Ｐ＜０．０５） 。ＭＭ４５Ｔ．ＬｉＩＬ１２ 与ＨＳＶＴＫＧＣＶ系统联合诱导的小鼠ＣＴＬ明显高于单     

国产重组白细胞介素－2的抗肿瘤研究

作者研究了国产重组白细胞介－２（ｒＩＬ－２）的抑瘤作用，延命作用及其诱导ＬＡＫ细胞的效应。小鼠移植性肿瘤用ｒＩＬ－２的较大剂量（２×１０￣４Ｕ／天）治疗，实验结果表明，抑瘤作用明显。由于靶细胞不同，ｒＩＬ－２的抑瘤率有差异。对Ｓ１８０的抑瘤率较差，对小鼠肝癌实体瘤（ＨＡＣ）的抑瘤作用较强。小鼠注射ｒＩＬ－２２×１０￣４Ｕ／天后肿瘤体积缩小，但２天不注射则逐渐增大。较大剂量的ｒＩＬ－２对荷瘤小鼠的延命作用非常明显（Ｐ＜０．００１）。接种瘤细胞后２３日，实验组死亡率为２０％，对照组死亡率为９０％。实验组虽瘤体甚大，小鼠不易死亡。用ｒＩＬ－２诱导的ＬＡＫ细胞并输入ｒＩＬ－２作荷瘤小鼠的过继性治疗其疗效较单用ｒＩＬ－２为优，粘附ＬＡＫ（Ａ－ＬＡＫ）的抑瘤率明显大于常规ＬＡＫ（Ｐ＜０．０２）。     

生长抑素 SMS201-995 对小鼠结肠腺癌肝转移瘤的实验研究

目的本研究观察生长抑素衍生物ＳＭＳ２０１┐９９５对ＢＡＬＢ／ｃ小鼠结肠腺癌（ＣＴ２６）肝转移瘤细胞周期的影响，检测血清ＣＥＡ水平的变化，并观察小鼠生存期的改变。方法采用流式细胞术。结果与对照组相比，ＳＭＳ２０１┐９９５治疗组的瘤细胞增殖指数和Ｓ期细胞百分比明显降低（Ｐ＜０．０１），而Ｇ０／Ｇ１期细胞百分比则明显增加（Ｐ＜０．０１）。治疗组血清ＣＥＡ水平较对照组显著降低（Ｐ＜０．０５），生存期明显延长。治疗组细胞增殖指数，Ｓ期和Ｇ０／Ｇ１期细胞百分比与血清ＣＥＡ的变化密切相关（相关系数与Ｐ值分别为：ｒ＝０．６６７７，Ｐ＜０．０５；ｒ＝０．７１７０，Ｐ＜０．０１；ｒ＝－０．６７０３，Ｐ＜０．０５）。结论ＳＭＳ２０１┐９９５对结肠腺癌（ＣＴ２６）肝转移性肿瘤的生长具有一定的抑制作用。     

生长抑素SMS201—995对小鼠结肠癌肝转移瘤的实验研究

本研究观察生长抑素衍生素ＳＭＳ２０１－９９５对ＢＡＬＢ／ｃ小鼠结肠腺癌肝转移瘤细胞周期的影响，检测血清ＣＥＡ水平的变化，并观察小鼠生存期的改变。采用流式细胞术。与对照组相比，ＳＭＳ２０１－９９５治疗组的瘤细胞增殖指数和Ｓ期细胞百分比明显降低（Ｐ〈０．０１）而Ｇ０／Ｇ１期细胞百分比则明显增加（Ｐ〈０．０１）。治疗组血清ＣＥＡ水平较对照组显著降低（Ｐ〈０．０５），生存期明显延长。治疗组细胞增殖指数，Ｓ     

温热低渗液联合洗必泰卡铂对胃癌腹膜移植瘤增殖活性的影响

目的探讨温热低渗液、洗必泰、卡铂或联合应用,对Ｓｙ８６Ｂ人胃癌小鼠腹膜移植瘤增殖活性抑制作用及其与直接杀伤效应的相关性。方法采用Ｂｒｄｕ体外标记、ＦＣＭ及ＲＩＡ技术检测,经４３℃双蒸馏水（ＤＤＷ）、ＤＤＷ加微量洗必泰（０．０５％）、卡铂（１０ｍｇ／ｋｇ）和４３℃ＤＤＷ加卡铂（１０ｍｇ／ｋｇ）处理后的腹水瘤细胞增殖指标。结果与对照组比较,各实验组瘤细胞的Ｂｒｄｕ标记指数（ＢｒｄｕＬＩ）减少２１．８％～７５．０％（Ｐ＜０．０５～０．０１）;Ｓ和Ｇ２／Ｍ期增殖细胞比率、增殖指数（ＰＩ）和ＤＮＡ指数（ＤＩ）显著下降（Ｐ＜０．０１）。瘤细胞的异倍体与二倍体ＤＮＡ核型比例分别为６４,７３,４６和１９;腹水上清中ＣＥＡ和ｈＥＧＦ含量消减（Ｐ＜０．０１）。ＢｒｄｕＬＩ、ＰＩ、ＤＩ、ＣＥＡ和ｈＥＧＦ５种指标与小鼠生存时间或瘤细胞数量之间相关性有显著意义（ｒ＝０．４９～０．８２,Ｐ＜０．０５～０．０１）。结论４种处理因素均有抑制瘤细胞增殖活性作用,以４３℃ＤＤＷ协同卡铂效果最佳。     

树突状细胞局部免疫抗瘤作用的初步研究

目的：探讨树突状细胞（ＤＣ）瘤内注射的局部免疫方式对小鼠Ｈ２２肿瘤的治疗效果。方法：体外诱导生成树突状细胞,经Ｈ２２肿瘤裂解抗原致敏,实验分为对照组、ＤＣ组和ＤＣ＋ＣｐＧ-ＯＤＮ组,分别与Ｔ细胞共培养,收获的Ｔ细胞与肿瘤细胞共培养,观察其对肿瘤细胞的杀伤。体内试验：ＢＡＬＢ／ｃ小鼠皮下接种Ｈ２２肿瘤细胞制作成荷瘤鼠,第４天时进行局部瘤内免疫治疗,分为３组：生理盐水组、ＤＣ组和ＤＣ＋ＣｐＧ-ＯＤＮ组,免疫治疗１０天后处死小鼠,观察其治疗小鼠Ｈ２２肿瘤的效果。结果：体外实验中,对照组、ＤＣ组和ＤＣ＋ＣｐＧ-ＯＤＮ组的肿瘤杀伤率分别为（１０.８０±３.２７）％、（３８.２６±５.６０）％和（４２.６６±９.００）％,后两组杀伤率均高于对照组（Ｐ＜０.０１）;体内实验中,生理盐水组、ＤＣ组和ＤＣ＋ＣｐＧ-ＯＤＮ组的平均瘤重（ｇ）分别为１.８０４±０.４２２、１.２１６±０.３３５和０.７３３±０.１９１（Ｐ＜０.０１）。结论：ＤＣ瘤苗局部瘤内注射可抑制小鼠Ｈ２２肿瘤的生长,联合应用非甲基化ＣｐＧ-ＯＤＮ可以明显提高抑瘤效果。     

mB7－1基因转染小鼠黑色素瘤细胞诱导的抗瘤效应研究

目的：研究共刺激Ｂ７－１（ＣＤ６０）在诱导有效的抗肿瘤免疫反应反应中所起的作用。方法：在体外,三种肿瘤细胞与同上鼠脾淋巴细胞混合培养（ＭＬＴＣＳ）后,测定淋巴细胞增殖指数（ＭＴＴ法）和特异杀伤活性（ＬＤＨ释放改良法）;ＭＴＴＩ地测定肿瘤细胞体外增殖能力后,将Ｂ１６－ｎｅｏ和Ｂ１６－ｍＢ７－１妆种于Ｃ５７ＢＬ／６小鼠皮下后观察成瘤期、荷瘤小鼠存活以及肿瘤结节生长速度。结果：与野生型Ｂ１６细胞和模拟转     

Dose of Adenoviral Vectors Expressing Interleukin-2 Plays an Important Role in Combined Gene Therapy with Cytosine Deaminase/5–Fluorocytosine: Preclinical Consideration

Using a syngeneic murine model, we investigated the therapeutic efficacy of combined gene therapy using adenoviral vectors expressing murine interleukin-2 (AdmIL-2) and Escherichia coli cytosine deaminase (AdCD). In a subcutaneous tumor model, tumor-bearing mice were treated with an intratumoral injection of adenoviral vectors and received an intraperitoneal administration of 5–fluorocytosine (5–FC). Only the mice treated with AdCD (2×10⁸ pfu) and an intermediate dose of AdmIL-2 (1×10⁶ pfu) survived significantly longer than mice treated with AdCD alone ( P <0.01). Moreover, 40% of these treated mice obtained complete remission from tumor-bearing status. The cytotoxicity of splenocytes obtained from the treated mice was related to the survival period. Tumor-specific cytotoxic T lymphocyte assay showed that the cell-mediated cytotoxic response was specific for parental tumor cells. In a hepatic metastasis model, mice treated with an intravenous administration of both AdCD (2×l0⁸ pfu) and an intermediate dose of AdmIL-2 (1×10⁶ pfu) demonstrated the most significant reduction of metastatic foci and the longest survival following a 5–FC administration. These results suggest that gene therapy combined with AdmIL-2 and AdCD may be a promising strategy for clinical application and, in addition, that translation of combined gene therapy from murine models into the clinical setting will require careful attention to the variables of cytokine expression levels in the design of clinical trials and in the evaluation of treatment efficacy.     

Cancer‐associated fibroblast‐targeted strategy enhances antitumor immune responses in dendritic cell‐based vaccine

Given the close interaction between tumor cells and stromal cells in the tumor microenvironment (TME), TME‐targeted strategies would be promising for developing integrated cancer immunotherapy. Cancer‐associated fibroblasts (CAFs) are the dominant stromal component, playing critical roles in generation of the pro‐tumorigenic TME. We focused on the immunosuppressive trait of CAFs, and systematically explored the alteration of tumor‐associated immune responses by CAF‐targeted therapy. C57BL/6 mice s.c. bearing syngeneic E.G7 lymphoma, LLC1 Lewis lung cancer, or B16F1 melanoma were treated with an anti‐fibrotic agent, tranilast, to inhibit CAF function. The infiltration of immune suppressor cell types, including regulatory T cells and myeloid‐derived suppressor cells, in the TME was effectively decreased through reduction of stromal cell‐derived factor‐1, prostaglandin E₂, and transforming growth factor‐β. In tumor‐draining lymph nodes, these immune suppressor cell types were significantly decreased, leading to activation of tumor‐associated antigen‐specific CD8⁺ T cells. In addition, CAF‐targeted therapy synergistically enhanced multiple types of systemic antitumor immune responses such as the cytotoxic CD8⁺ T cell response, natural killer activity, and antitumor humoral immunity in combination with dendritic cell‐based vaccines; however, the suppressive effect on tumor growth was not observed in tumor‐bearing SCID mice. These data indicate that systemic antitumor immune responses by various immunologic cell types are required to bring out the efficacy of CAF‐targeted therapy, and these effects are enhanced when combined with effector‐stimulatory immunotherapy such as dendritic cell‐based vaccines. Our mouse model provides a novel rationale with TME‐targeted strategy for the development of cell‐based cancer immunotherapy.     

Antitumor activity of Ge-132, a new organogermanium compound, in mice is expressed through the functions of macrophages and T lymphocytes

The antitumor activity of Ge-132 against a variety of allogeneic and syngeneic murine ascites tumors was first evaluated. The antitumor effects of Ge-132 were observed when mice inoculated with Ehrlich carcinoma (allogeneic) or RL male 1 leukemia (syngeneic) cells were treated orally. However, Ge-132 had no activity on a T-cell lymphoma (EL 4, syngeneic) or a methylcholanthrene-induced fibrosarcoma (Meth-A, syngeneic). The antitumor effect of Ge-132 in mice was related to the dose administered as well as the administration schedule. The antitumor activity of Ge-132 was next studied in mice pretreated with some blockers against immunocompetent cells. The antitumor efficacy of Ge-132 was not observed when tumor-bearing mice were treated with trypan blue and carrageenan or monoclonal anti-Thy 1.2 antibody. However, when natural killer cells were eliminated from mice bearing RL male 1 or Ehrlich ascites tumors by treatment with anti-asialo GM 1 antiserum, the antitumor efficacy of the compound was unchanged. These results suggest that Ge-132 is effective against certain ascites tumors regardless of whether the tumor is syngeneic or allogeneic. Further, its effect might be expressed through host defense mechanisms, including macrophages and/or T lymphocytes.     

A novel small-molecule inhibitor of transforming growth factor beta type I receptor kinase (SM16) inhibits murine mesothelioma tumor growth in vivo and prevents tumor recurrence after surgical resection

Malignant mesothelioma is an aggressive and lethal pleural cancer that overexpresses transforming growth factor beta (TGFbeta). We investigated the efficacy of a novel small-molecule TGFbeta type I receptor (ALK5) kinase inhibitor, SM16, in the AB12 syngeneic model of malignant mesothelioma. SM16 inhibited TGFbeta signaling seen as decreased phosphorylated Smad2/3 levels in cultured AB12 cells (IC(50), approximately 200 nmol/L). SM16 penetrated tumor cells in vivo, suppressing tumor phosphorylated Smad2/3 levels for at least 3 h following treatment of tumor-bearing mice with a single i.p. bolus of 20 mg/kg SM16. The growth of established AB12 tumors was significantly inhibited by 5 mg/kg/d SM16 (P < 0.001) delivered via s.c. miniosmotic pumps over 28 days. The efficacy of SM16 was a result of a CD8+ antitumor response because (a) the antitumor effects were markedly diminished in severe combined immunodeficient mice and (b) CD8+ T cells isolated from spleens of mice treated with SM16 showed strong antitumor cytolytic effects whereas CD8+ T cells isolated from spleens of tumor-bearing mice treated with control vehicle showed minimal activity. Treatment of mice bearing large tumors with 5 mg/kg/d SM16 after debulking surgery reduced the extent of tumor recurrence from 80% to <20% (P < 0.05). SM16 was also highly effective in blocking and regressing tumors when given p.o. at doses of 0.45 or 0.65 g/kg in mouse chow. Thus, SM16 shows potent activity against established AB12 malignant mesothelioma tumors using an immune-mediated mechanism and can significantly prevent tumor recurrence after resection of bulky AB12 malignant mesothelioma tumors. These data suggest that ALK5 inhibitors, such as SM16, offer significant potential for the treatment of malignant mesothelioma and possibly other cancers.     

Effective anti-metastatic melanoma vaccination with tumor cells transfected with MHC genes and/or infected with newcastle disease virus (NDV)

The therapeutic efficacy of active immunization with B16-F10.9 melanoma cells transfected with syngeneic major histocompatibility complex (MHC) class-l genes, modified by infection with Newcastle Disease virus (NDV) or modified by both treatments, was compared. B16-F10.9 tumor-bearing mice were treated at various stages of tumor growth and metastasis with irradiated, modified tumor-cell vaccines. Irradiated tumor cells and H-2D^b transfectants did not stimulate anti-tumor immunity while H-2K^b transfectants and NDV-modified F10.9 cells showing low and high expression of MHC class-l genes efficiently prevented metastasis of small established tumors. NDV-modified parental-cell vaccines functioned optimally and improved overall survival by about 60%, also at early stages of metastasis establishment. A synergistic effect of H-2K^b expression and virus modification on rejection of micrometastases was observed in mice bearing advanced tumors. Postoperative vaccination of mice carrying multiple metastases with NDV-modified vaccines caused significant, but incomplete, reduction of metastatic tumor load. The therapeutic effect of NDV-modified tumor vaccines was dependent on multiple immune mechanisms. Depletion of CD8, CD4 or NK cells by in vivo treatment with monoclonal antibodies reversed the immunotherapeutic effects of the vaccine. Thus, tumor xenogenization and gene modification may act synergistically to vaccinate against advanced tumors, while single modalities can effectively vaccinate against metastasis at early stages of tumor growth.     

Augmentation of antitumor immune response by trinitrophenyl (TNP)-reactive helper T-cells: enhanced induction of tumor-specific Lyt-1+2- T-cell-mediated delayed-type hypersensitivity from spleen cells of tumor-bearing mice by TNP helpers

Spleen cells from X5563 tumor-bearing syngeneic C3H/HeN mice were stimulated in vitro with trinitrophenyl (TNP)-modified or unmodified X5563 tumor cells. TNP-reactive helper T-cells obtained from TNP-primed C3H/HeN mice were added to the above cultures in an attempt to augment the induction of anti-X5563 delayed-type hypersensitivity (DTH) responses. The DTH responses were measured by adoptive transfer of cultured cells together with unmodified X5563 cells into footpads of syngeneic mice. Cultures of spleen cells from tumor-bearing mice plus X5563 or TNP-modified X5563 cells failed to generate anti-X5563 DTH responses. In contrast, addition of TNP-helper T-cells to the cultures resulted in appreciable DTH as well as in cytotoxic responses to X5563 tumor cells. Demonstration of this immunity was dependent on the presence of TNP-X5563 tumor cells as stimulators during the culture period. The anti-X5563 DTH effector cells augmented by TNP helpers were found to be of the Lyt-1+2- phenotype and were tumor specific, since DTH responses were observed when the cultured cells were injected with X5563 but not when injected with another syngeneic tumor. These results demonstrate that TNP-helper T-cells are capable of augmenting the induction of tumor-specific Lyt-1+2- T-cell-mediated DTH responses from lymphoid cells of tumor-bearing mice upon the stimulation of TNP-reactive tumor cells. The results are discussed in relation to: a previously described tumor-specific immunotherapy model in which a growing tumor regressed by virtue of TNP helpers and the implications of augmenting induction of tumor-specific DTH responses in antitumor resistance.     

不同微生物佐剂S-180瘤苗的免疫效应和抑瘤作用

 目的　比较肿瘤主动特异性免疫治疗中具有佐剂作用的白色念珠菌、李斯特菌及卡介苗的免疫调节效应和抑瘤作用。方法　选择白色念珠菌、李斯特菌、卡介苗各自联合小鼠S-180肿瘤疫苗,皮下免疫接种荷瘤小鼠,检测小鼠脾细胞IL-2、IFN-产生水平,腹腔MTNF-α产生水平,观察荷瘤小鼠瘤体重量和存活期。结果　三种微生物佐剂均能协同瘤苗增强免疫小鼠IL-2、IFN-和TNF-α的产生能力(P<0.01,0.05),有效抑制足垫部移植瘤的生长,抑制率在62.8%～75.8%之间,显著高于单独注射瘤苗组(P<0.01),延长腹腔植瘤小鼠平均存活期7～14天,白色念珠菌、李斯特菌协同提高腹腔植瘤小鼠存活率20%。结论　白色念珠菌和李斯特菌与卡介苗具有同样的佐剂效应,能够协同瘤苗有效抑制肿瘤生长。     

Importance of T-cells and macrophages in the antitumor activity of carboxyethylgermanium sesquioxide (Ge-132)

The purpose of this study was to investigate the effective mechanisms of Ge-132, an organogermanium compound with immunomodulatory activity, on experimental murine ascites tumors. The antitumor effects of Ge-132 were observed when mice inoculated with Ehrlich carcinoma (allogeneic) or RL male 1 leukemia (syngeneic) cells were treated orally. However, Ge-132 had no activity on EL-4 lymphoma (syngeneic) or Meth A fibrosarcoma (syngeneic). The antitumor activity of Ge-132 was not observed when tumor-bearing mice were treated with trypan blue, carrageenan, or monoclonal anti-Thy 1.2 antibody. However, when natural killer (NK) cells were eliminated from mice bearing RL male 1 or Ehrlich ascites tumors by treatment with anti-asialo GM1 antiserum, the antitumor activity of the compound was unchanged. This suggests that Ge-132 was effective against certain ascites tumors regardless of whether the tumor was syngeneic or allogeneic. Furthermore, its effect might be expressed through host defense mechanisms, including macrophages and/or T-cells.     

Effect of a single injection of cyclophosphamide on immunization therapy of metastases remaining after excision of dermal primary tumors in guinea pigs

Guniea pigs with established (7 or 14 days old) syngeneic dermal tumors and metastases in the draining lymph nodes were unsuccessfully treated by excision of the dermal tumors and specific immunization. The vaccines consisted of killed BCG in oil in an emulsified form admixed with mitomycin C treated or irradiated tumor cells. The therapeutic failure to eradicate the metastases was overcome by an additional treatment with a single injection of cyclophosphamide prior to excision of the primary tumor and immunization. It is assumed that cyclophosphamide destroys suppressor elements in the tumor-bearing guinea pigs and, in this way, augments the therapeutic effects of specific immunization.     

Efficient inducation of local and systemic antitumor immune response by liposome-mediated intratumoral co-transfer of interleukin-2 gene and interleukin-6 gene.

Interleukin 2 (IL-2) expressing plasmid and interleukin 6 (IL-6)-expressing plasmid were encapsulated in liposome and administrated intratumoraly into tumor-bearing mice 4 days after subcutaneous inoculation of B16F10 melanoma cells. The results showed that treatment of tumor-bearing mice with IL-2 gene or IL-6 gene transfer inhibited the growth of subcutaneous tumor and prolonged the survival of tumor-bearing mice significantly when compared with the treatment of PBS or control gene transfer mediated by liposome (P < 0.01). Combined transfer of IL-2 gene and IL-6 gene was found to elicit inhibitory effects on the growth of B16F10 tumor more significantly and prolonged the survival period of tumor-bearing mice more obviously. We investigated the local immunity in tumor microenvironment and found that IL-2 and IL-6 gene transfer could significantly increase the expression of lymphocyte function-associated antigen-1 on tumor infiltrating lymphocytes (TIL) and MHC-I molecule on tumor cells freshly isolated from the tumor mass. The NK and CTL activity of TIL increased markedly after the combined transfer of these two cytokine genes. We also observed the systemic antitumor immune response in the tumor-bearing mice and demonstrated that NK and CTL activity of splenocytes and the production of IL-2, tumor necrosis factor and interferon-gamma from splenocytes increased obviously in mice after the combined transfer of IL-2 and IL-6 gene. In conclusion, local and systemic antitumor immunity of the tumor-bearing host could be induced efficiently after the combined gene transfer. The enhanced specific and non-specific antitumor immunity might be responsible for the more potent antitumor effects of the combined gene therapy.