Protective antitumor activity through dendritic cell immunization is mediated by NK cell as well as CTL activation

Dendritic cells (DCs) are potent professional antigen-presenting cells (APC) capable of inducing the primary T cell response to antigen. Although tumor cells express target antigens, they are incapable of stimulating a tumor-specific immune response due to a defect in the costimulatory signal that is required for optimal activation of T cells. In this work, we describe a new approach using tumor-DC coculture to improve the antigen presenting capacity of tumor cells, which does not require a source of tumor-associated antigen. Immunization of a weakly immunogenic and progressive tumor cocultured with bone marrow-derived DCs generated an effective tumor vaccine. Immunization with the cocultured DCs was able to induce complete protective immunity against tumor challenges and was effective for the induction of tumor-specific CTL (cytotoxic T lymphocyte) activity. Furthermore, high NK cell activity was observed in mice in which tumors were rejected. In addition, immunization with tumor-pulsed DCs induced delayed tumor growth, but not tumor eradication in tumor-bearing mice. Our results demonstrate that coculture of DCs with tumors generated antitumor immunity due to the NK cell activation as well as tumor-specific T cell. This approach would be useful for designing tumor vaccines using DCs when the information about tumor antigens is limited.     

跨膜型超抗原金黄色葡萄球菌肠毒素A融合蛋白的抗肿瘤作用

目的　为扩大超抗原金黄色葡萄球菌肠毒素A(SEA)的抗瘤谱 ,制备跨膜型SEA融合蛋白 ,研究该蛋白制备的肿瘤疫苗的抗肿瘤作用。方法　在荷B16黑色素瘤的C5 7BL/ 6小鼠上 ,观察跨膜型SEA融合蛋白制备的肿瘤疫苗对荷瘤小鼠的免疫治疗作用和免疫保护作用 ,并通过乳酸脱氢酶 (LDH)释放法检测治疗组和免疫组小鼠脾细胞的天然杀伤细胞(NK)和细胞毒性T细胞 (CTL)活性。结果　融合蛋白制备的肿瘤疫苗能够显著抑制荷瘤小鼠肿瘤的生长 ,并延长其生存期 ,其脾细胞的NK和CTL活性显著增强。同时 ,该肿瘤疫苗对同种肿瘤细胞攻击可产生较强的免疫保护作用。结论　跨膜型SEA融合蛋白制备的肿瘤疫苗具有显著的抗肿瘤作用 ,可有效激发荷瘤小鼠机体的特异性和非特异性抗肿瘤免疫应答 ,增强CTL和NK活性。     

Antitumor immunity of human SART3 gene vaccine against mouse tumor in vitro/vivo

To determine whether squamous cell carcinoma antigen recognized by human T cell 3 (SART3) gene can induce antitumor immunity against tumor cells which express the gene, we constructed mouse tumor cells expressing human SART3 (LM8-SART3) and carried out experiments in vitro/vivo. After subcutaneous injection with SART3 gene vaccine, cytotoxic T lymphocyte (CTL) activity in vitro was measured using Cell Counting Kit-8. As for the in vivo part, C3H mice were divided into several groups. One group was challenged with tumor cells after immunity. Another group was treated with the vaccine after tumor implantation. It was found that human SART3 DNA vaccine can elicit a specific CTL reaction from the mouse splenocytes. After vaccination, tumor occurrence and tumor growth speed was reduced. The vaccine also shows activity in tumor treatment. We conclude that the human SART3 DNA vaccine can induce antitumor ability against tumor cells expressing human SART3 (LM8-SART3) in vitro/vivo which may provide new possibilities in antitumor therapy.     

螺旋藻多糖硫酸酯化修饰前后抗肿瘤及免疫活性的研究

比较螺旋藻多糖硫酸酯化修饰前后体内外抗肿瘤及免疫活性.采用MTT比色法研究药物在体外对人肿瘤细胞株的抑制作用,促进正常小鼠脾淋巴细胞的增殖活性以及对荷瘤小鼠NK和CTL细胞活性的影响.采用移植性肿瘤实验方法考察了药物对小鼠S180肉瘤的抑制作用.结果显示,螺旋藻多糖（NPSP）对肿瘤细胞株几乎无细胞毒作用,硫酸酯化螺旋藻多糖（SNPSP）对肿瘤细胞株具有显著的细胞毒作用,其中对SMMC-7721人肝癌细胞株抑制率最高达50%.NPSP50 mg/kg对小鼠S180肉瘤无抑制,相同剂量的SNPSP对小鼠S180肉瘤的抑制率达35.42%.NPSP具有促进脾淋巴细胞增殖作用,但对ConA和LPS诱导的脾淋巴细胞增殖反应无促进作用,SNPSP促进脾淋巴细胞增殖作用较NPSP增强,同时对ConA和LPS诱导的脾淋巴细胞增殖反应也具有明显的促进作用.NPSP和SNPSP均能促进荷瘤小鼠NK细胞和CTL细胞活性,其中SNPSP促进CTL细胞活性较NPSP增强.     

泥鳅多糖对小鼠脾细胞免疫应答的影响

目的:研究泥鳅多糖对小鼠脾细胞免疫应答的影响.方法:分别给正常小鼠、刀豆蛋白(ConA)或左旋咪唑免疫增强小鼠、环磷酰胺免疫抑制小鼠腹腔注射提取的泥鳅多糖,连续给药7d.用~H-胸苷掺入法测定T淋巴细胞的增殖.用~(51)Cr同位素标记法测定细胞毒T淋巴细胞的细胞毒性和天然杀伤细胞的活性.结果:泥鳅多糖5或10mg·kg~(-1)·d~(-1)可以提高T淋巴细胞的增殖,并增强细胞毒T淋巴细胞的细胞毒性和天然杀伤细胞的活性,还能增强ConA解除环磷酰胺对T淋巴细胞增殖抑制的能力,抑制率从环磷酰胺对照组的51.4％分别降低到18.2％和35.1％.而且,给予小鼠10或20mg·kg~(-1)·d~(-1)的泥鳅多糖,可以恢复环磷酰胺所致的天然杀伤细胞活性降低.结论:泥鳅多糖能增强小鼠脾细胞中T细胞、细胞毒T淋巴细胞和天然杀伤细胞的活性.     

Effective tumor immunity to melanoma mediated by B16F10 cancer stem cell vaccine

Although tumor vaccines have been considered a promising immunotherapy approach, therapeutic tumor vaccines are mostly disappointing in the clinic due to vaccine weak immunogenicity. Cancer stem cells (CSCs) may broaden the antigenic breadth and effectively induce the immune responses against autologous cancer cells. Here we report on the development of the B16F10 CD133⁺ CD44⁺ CSCs (B16F10 CSCs) vaccine to induce tumor immunity to melanoma in mice. Efficacy of against melanoma was evaluated by analysis of tumor growth and mouse survival. Immunogenicity was assessed by ELISA and flow cytometric assays, including serum cytokines, cytotoxic activity of NK cells and splenocytes in the immunized mice. The results showed that the B16F10 CSC vaccine resulted in tumor shrinkage and mouse lifespan extension. The cytotoxic activity and IFN-γ level were significantly increased in mice immunized with B16F10 CSC vaccine compared with the mice immunized with control vaccines. Additionally, New York esophageal squamous cell carcinoma-1, an efficient tumor associated antigen over-expressed by B16F10 CSCs, was markedly reduced in expression in melanoma tissue, suggesting decrease of CSC subpopulation due to B16F10 CSC vaccination. Collectively, the findings may represent a new powerful approach for treatment of melanoma by B16F10 CSC vaccination.     

Immunotoxicity of N,N-diethylaniline in mice: effect on natural killer activity, cytotoxic T lymphocyte activity, lymphocyte proliferation response and cellular components of the spleen

We previously found that N,N-diethylaniline increased the frequency of sister chromatid exchange (SCE) of human lymphocytes to about five times that of the control value, and was as toxic as cyclophosphamide used as a positive control for SCE. To explore whether N,N-diethylaniline affects the function of lymphocytes, we evaluated its immunotoxicity using CBA/N mice. The mice were divided into four groups and received 0, 100, 200, or 400 mg/kg body weight of N,N-diethylaniline by subcutaneous injection. The following items were investigated on days 3 and 7 after injection: body weight, weight of spleen, number of splenocytes, natural killer (NK) and cytotoxic T lymphocyte (CTL) activities, and concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated lymphocyte proliferation using splenocytes. The following splenocyte phenotypes were also quantified by flow cytometry: (1) B cells; (2) total T cells; (3) CD4⁺ and CD8⁺ T cells; (4) NK; (5) macrophages and (6) nucleated erythrocytes. The splenic NK and CTL activities in exposed groups significantly decreased compared to the control in a dose-dependent manner and lymphocytes from the 200 and 400 mg/kg groups showed significantly higher spontaneous proliferation. The weight of the spleen and number of splenocytes were significantly higher in exposed groups than in the control. N,N-Diethylaniline also increased the percentages of macrophages, nucleated erythrocytes and B cells in the spleen. On the other hand, N,N-diethylaniline did not affect LPS-stimulated B cell and Con A-stimulated T cell proliferation, or the percentages of NK, total T, and CD4⁺ and CD8⁺ T cells in the spleen or the body weight of mice. The above findings indicated that N,N-diethylaniline selectively inhibited splenic NK and CTL activity and this inhibition was due to decreased NK and CTL functions, but not due to changes in the numbers of splenic NK and T cells.     

Immunotherapy of Human Neuroblastoma Using Umbilical Cord Blood-Derived Effector Cells

Tumors of the nervous system, including neuroblastoma and glioblastoma, are difficult to treat with current therapies. Despite the advances in cancer therapeutics, the outcomes in these patients remain poor and, therefore, new modalities are required. Recent literature demonstrates that cytotoxic effector cells can effectively kill tumors of the nervous system. In addition, we have previously shown that umbilical cord blood (UCB) contains precursors of antitumor cytotoxic effector cells. Therefore, to evaluate the antitumor potential of UCB-derived effector cells, studies were designed to compare the in vitro and in vivo antitumor effects of UCB- and peripheral blood (PB)-derived antigen-nonspecific and antigen-specific effector cells against tumors of the nervous system. Mononuclear cells (MNCs) from UCB were used to generate both interleukin-2 (IL-2)-activated killer (LAK) cells and tumor-specific cytotoxic T lymphocytes (CTLs). UCB-derived LAK cells showed a significant in vitro cytotoxicity against IMR-32, SK-NMC, and U-87 human neuroblastoma and glioblastoma, respectively. In addition, the CTLs generated using dendritic cells primed with IMR-32 tumor cell lysate showed a selective cytotoxicity in vitro against IMR-32 cells, but not against U-87 or MDA-231 cells. Furthermore, treatment of SCID mice bearing IMR-32 neuroblastoma with tumor-specific CTLs resulted in a significant (p < 0.01) inhibition of tumor growth and increased overall survival. Thus, these results demonstrate the potential of UCB-derived effector cells against human neuroblastoma and warrant further preclinical studies.     

An aqueous extract of Limoniastrum guyonianum gall induces anti-tumor effects in melanoma-injected mice via modulation of the immune response

The objectives of this study were to evaluate the in vitro and in vivo anti-tumor potential of the aqueous gall extract (G extract) from Limoniastrum guyonianum and to elucidate its immunological mechanisms, in part, by assessing its effects on the growth of transplanted tumors and the immune response in these tumor-bearing mice. Here, mice were inoculated with B16F10 mouse tumor cells and then treated intraperitoneally with G extract at 25 or 50 mg extract/kg BW for 7, 14, or 21 days. At each timepoint, effects of the extract on the tumor growth, splenocytes proliferation, NK cell activity, and CTL activity among splenocytes isolated from the mice were measured. G extract-induced tumor growth inhibition was associated with characteristic apoptotic changes in the tumor cells, like nuclear condensation. In addition, the extract inhibited melanin synthesis and tyrosinase activity among melanoma cells in a concentration-related manner. G extract did not only significantly inhibit the growth of the transplantable tumor, but also remarkably increased splenocytes proliferation and both NK and CTL activities in tumor-bearing mice. The extract was also seen to have promoted lysosomal activity of host macrophages and gave rise to enhanced cellular anti-oxidant activity in several cell types in mice.     

Antitumor cells found in tumor-bearing mice given ubenimex

Antitumor effector cells in spleens of tumor-bearing mice given ubenimex were investigated. The administration of ubenimex, starting 7 days after the tumor inoculation, was effective in inhibiting growth of IMC carcinoma. Spleen cells taken from these mice showed a marked suppression of the tumor growth by the WINN assay. The antitumor activity of spleen cells was reduced by treatment to remove T cells or NK cells, whereas spleen cell preparations enriched for T cells showed the strongest antitumor activity. Moreover, NK activity against YAC-1 cells was found in the spleen. These results indicate that the administration of ubenimex to IMC carcinoma-bearing mice generates cytotoxic T cells and NK cells in the spleen. The antitumor effect of ubenimex was not observed in X-ray-irradiated and in anti-asialo GM1 serum-treated mice.     

CD_(44)v_6修饰DC融合瘤苗体外抗结肠癌作用的研究

目的小鼠提取的树突状细胞(DC)和小鼠结肠癌细胞CT26.WT共培养、融合,CD44v6基因来修饰融合细胞,研究CD44v6修饰DC融合瘤苗体外抗结肠癌的作用机制,为肿瘤预防及免疫治疗提供实验依据。方法①在聚乙二醇的作用下,DC细胞和CT26.WT细胞共培养、融合,利用HAT/HT筛选系统筛选出纯净DC融合细胞。在脂质体的作用下,将pBud-CD44v6转染到DC融合细胞中表达;②体外实验观察DC融合瘤苗对小鼠结肠癌细胞的杀灭作用。结果构建了基因CD44v6修饰的DC/CT26.WT肿瘤融合疫苗;实验组细胞的淋巴细胞毒(CTL)活性明显高于对照组。结论 CD44v6修饰的DC融合瘤苗可有效诱导T淋巴细胞产生强大抗结肠癌作用。     

Dendritic cell vaccine modified by Ag85A gene enhances anti-tumor immunity against bladder cancer

The ability of dendritic cells to provide all the signals required for T-cell activation makes them an ideal cancer vaccine platform. With the use of established DC2.4 cell line, originated from C57BL/6 mice and developed by superinfecting GM-CSF transduced bone marrow cells with myc and raf oncogenes, we investigated whether the DC 2.4 cell line transfected with Ag85A gene could enhance immunity against bladder cancer. Both phenotypic and functional analyses of Ag85A-DCs were done with use of FCM and T cell proliferation test. The cytotoxicity of Ag85A-DCs loaded with tumor cell lysate was verified by LDH. Finally, the production of interferon gamma was assayed by both ELISA and FCM. The immunotherapeutic effect of DC vaccine on murine bladder cancer was assessed pharmacologically and pathologically. Our results showed that Ag85A gene transfected DCs expressed high levels of key surface markers such as CD80, CD86 and MHC-II. The CTL primed with MB49 lysate-pulsed Ag85A-DCs elicits higher activity against MB49 tumor cells and upregulated level of IFN-γ production. Furthermore, the significant inhibitive effect on tumor growth in mice was found in the group of Ag85A-DC vaccine. The infiltration of CD4(+) or CD8(+) T cell within established tumor treated by Ag85A-DC vaccine significantly increased as compared with control groups. It is therefore concluded that DCs engineered by Ag85A gene exerts enhanced anti-tumor immunity against bladder cancer and this study might provide a meaningful mode of action with the use of Ag85A engineered DC vaccination in anti-cancer immunotherapy.     

Acid-switchable nanoparticles induce self-adaptive aggregation for enhancing antitumor immunity of natural killer cells

Deficiency of natural killer (NK) cells shows a significant impact on tumor progression and failure of immunotherapy. It is highly desirable to boost NK cell immunity by upregulating active receptors and relieving the immunosuppressive tumor microenvironment. Unfortunately, mobilization of NK cells is hampered by poor accumulation and short retention of drugs in tumors, thus declining antitumor efficiency. Herein, we develop an acid-switchable nanoparticle with self-adaptive aggregation property for co-delivering galunisertib and interleukin 15 (IL-15). The nanoparticles induce morphology switch by a decomposition-metal coordination cascade reaction, which provides a new methodology to trigger aggregation. It shows self-adaptive size-enlargement upon acidity, thus improving drug retention in tumor to over 120 h. The diameter of agglomerates is increased and drug release is effectively promoted following reduced pH values. The nanoparticles activate both NK cell and CD8⁺ T cell immunity in vivo. It significantly suppresses CT26 tumor in immune-deficient BALB/c mice, and the efficiency is further improved in immunocompetent mice, indicating that the nanoparticles can not only boost innate NK cell immunity but also adaptive T cell immunity. The approach reported here provides an innovative strategy to improve drug retention in tumors, which will enhance cancer immunotherapy by boosting NK cells.     

枸杞粗多糖的免疫活性

为进一步分离纯化枸杞多糖并进行深入的免疫药理学研究 ,应用淋巴细胞增殖 ,溶血空斑 ,杀伤性T淋巴细胞 (CTL)杀伤活性测定 ,酶联免疫测定法和噻唑蓝等方法研究了枸杞粗多糖 (LBP)的免疫活性特点 .结果发现 :口服给予LBP对LACA小鼠脾细胞增殖反应和抗体生成反应均具有明显的促进作用 ,但对CTL细胞特异性杀伤P815瘤细胞的杀伤活性无明显影响 ;明显增加快速老化模型小鼠(SAMP8)脾抗体生成细胞的数目 ,升高脾细胞产生抗体IgG水平 .结果提示 ,LBP是枸杞子中主要免疫活性成分 ,促进或改善体液免疫功能可能是其对免疫系统的主要作用之一 .     

致敏树突状细胞疫苗抗小鼠乳腺癌的实验研究

目的研究以EMT6乳腺癌细胞致敏的树突状细胞(DC)疫苗的抗肿瘤作用。方法无菌取小鼠骨髓细胞,在体外培养条件下经细胞因子诱导为DC,用EMT6肿瘤细胞冻融抗原冲击致敏DC,检测经DC免疫产生的细胞毒T淋巴细胞(CTL)体外杀伤肿瘤细胞的活性。建立EMT6荷瘤小鼠模型,随机分为实验组、实验对照组和空白对照组,于肿瘤接种后第7、14天给予相应DC疫苗治疗,观察致敏DC免疫对小鼠乳腺肿瘤模型的治疗作用。结果致敏DC诱导生成的特异性CTL在体外对肿瘤细胞可产生杀伤作用,与PBS对照组比较,差异有显著性(P<0.05);经致敏DC注射免疫后,小鼠移植瘤得到抑制,与PBS对照组比较,差异有显著性(P<0.05)。结论以EMT6乳腺癌细胞致敏的树突状细胞(DC)疫苗在体外和小鼠体内均显示了抗肿瘤作用。     

NK cell-based cancer immunotherapy

The identification of spontaneous antitumor immune responses in cancer patients and the demonstration that an intact immune system can prevent against certain forms of malignancies invigorated research efforts in the development of cancer immunotherapies. To date, numerous and diversified approaches are being investigated, thereby providing new means by which to mobilize the cellular and molecular elements of the immune system in order to destroy established cancers. While it is appreciated that tumor-specific cytotoxic T lymphocytes play a critical role in successful immunotherapy, it is becoming increasingly apparent that cellular components of both the innate and the adaptive arms of the immune system can control tumor growth. In particular, natural killer (NK) cells are emerging as key players in the cross-talk between innate and adaptive immunity. With the uncovering of the regulatory mechanisms governing NK cell biology, new immunotherapies based on the harnessing of NK cell antitumor activity are now being developed. In this review, we summarize the role of NK cells in the control of tumor growth and discuss potential cancer therapies incorporating NK cell-mediated antitumor activity.     

CpG oligodeoxynucleotide-induced immunity prevents growth of germinal center-derived B lymphoma cells

Therapeutic efficacy of CpG oligodeoxynucleotide (ODN) ISS 1018 was tested in a murine B cell lymphoma model. Previous studies showed that the B lymphoma cells of SJL mice stimulate vigorous proliferation of host CD4(+) TH cells that is unaccompanied by development of tumor-specific CTL. In the presence of ISS 1018, however, tumor cells stimulated high levels of CTL activity in vitro, and this cytotoxic activity was inhibited when anti-IL-12 mAb was added to the cultures. Tumor cells pre-incubated with ISS 1018 were also able to generate CTL without addition of exogenous ODN, and FACS analysis revealed that following incubation with ISS 1018 for 24 h, tumor cells exhibited upregulation of MHC I, MHC II, and co-stimulatory molecule CD80. Finally, tumor-injected mice treated with ISS 1018 showed significantly less growth of tumor cells in lymph nodes and spleen, and exhibited prolonged survival compared to mice treated with a control ODN. The documented effects of CpG ODNs to stimulate cytokines, such as IL-12, from antigen presenting cells, and to upregulate expression of MHC Class I and Class II, as well as co-stimulatory molecules on tumor cells, are also the likely mechanisms by which CTL are generated by ISS 1018 in the SJL B cell lymphoma model.     

灵芝孢子粉对荷瘤小鼠树突状细胞的影响及其抗瘤效应

目的通过研究灵芝孢子粉对荷H22肝癌小鼠髓源性树突状细胞(DC)的影响及其抗肿瘤效应,探讨其抗肿瘤机制。方法应用不同浓度灵芝孢子粉(1、2、3g·kg-1·d-1)连续14d灌胃荷瘤小鼠后,处死小鼠,无菌获取骨髓细胞,粒细胞巨噬细胞刺激因子(GMCSF)和白细胞介素(IL)4体外诱导骨髓细胞生成DC,同时培养液中继续加入不同浓度灵芝孢子粉(0.8、3.2、12.8mg/L)。通过显微镜、流式细胞仪检测技术及细胞毒性实验观察不同浓度灵芝孢子粉对DC的影响,并通过脾指数、胸腺指数及肿瘤抑制率来观察其抗肿瘤效应。结果灵芝孢子粉能够促进荷瘤小鼠髓源性DC的分化、成熟及表面分子CD11a、CD86的表达,增强DC诱导的细胞毒性T淋巴细胞反应;灵芝孢子粉能够使荷瘤小鼠免疫器官脾脏和胸腺的重量增加,并明显抑制肿瘤的生长,存在量效关系。结论本实验表明灵芝孢子粉能够通过刺激DC的分化成熟,提高其抗原提呈能力,进而起到提高机体细胞免疫,抑制肿瘤生长的作用。     

An mRNA vaccine elicits STING-dependent antitumor immune responses

Lipid-formulated RNA vaccines have been widely used for disease prevention and treatment, yet their mechanism of action and individual components contributing to such actions remain to be delineated. Here, we show that a therapeutic cancer vaccine composed of a protamine/mRNA core and a lipid shell is highly potent in promoting cytotoxic CD8⁺ T cell responses and mediating anti-tumor immunity. Mechanistically, both the mRNA core and lipid shell are needed to fully stimulate the expression of type I interferons and inflammatory cytokines in dendritic cells. Stimulation of interferon-β expression is exclusively dependent on STING, and antitumor activity from the mRNA vaccine is significantly compromised in mice with a defective Sting gene. Thus, the mRNA vaccine elicits STING-dependent antitumor immunity.     

Cancer immunotherapeutic effects of novel CpG ODN in murine tumor model

While CpG oligodeoxynucleotides (ODN) are excellent candidates for cancer immunotherapeutics, the numbers of usable CpG ODNs are limited in current clinical settings. To resolve this, we investigated whether novel CpG ODN (KSK-CpG) would be an effective immunotherapeutic in a murine tumor model by affecting in vivo and in vitro parameters, such as survival span, the number of tumor nodules, natural killer (NK) cell and cytotoxic T lymphocyte (CTL) activity and interleukin (IL)-6 or IL-12 cytokine release in splenocytes. We found that KSK-CpG was effective in the murine cancer model by way of prolonging survival span, reducing the number of tumor nodules, augmenting NK cell and CTL cytotoxicity, as well as evoking IL-6 and IL-12 cytokine release in splenocytes. Collectively, these data demonstrate that KSK-CpG is active against the highly malignant B16BL6 and EL4 tumor mouse model via innate immune augmentation.