Anti-tumor effects of interleukin-4 and interleukin-5 against mouse B cell lymphoma and possible mechanisms of their action.

We investigated the anti-tumor effects of recombinant mouse interleukin (IL)-4 and IL-5 by using a transplantable B cell lymphoma 38C13 cell line as a model. Daily local administration of either IL-4 or IL-5 produced moderate but significant inhibition of the rate of local tumor growth and prolongation of mean survival time (MST) in syngeneic C3H/HeJ mice; these anti-tumor effects appeared to plateau at low doses. Histopathologic and immuno-histochemical examination revealed necrotic changes in the cytokine-treated tumors, associated with infiltration of inflammatory cells such as eosinophils, macrophages, and lymphocytes. The infiltrating lymphocytes were found to be Thy-1.2+ T cells. To elucidate the importance of T cells, the rate of tumor growth and the MSTs were compared between athymic T cell-deficient BALB/c nude mice and immunocompetent C3H/HeJ mice. In the nude mice the transplanted tumor grew more rapidly and the MST was shorter than in the normal mice, suggesting a significant contribution of infiltrating T cells in the anti-tumor effects of the interleukins. Lastly, in vitro, growth inhibition of the 38C13 cells was observed in a dose-dependent manner at relatively high concentrations of either cytokine. Therefore, we conclude that both IL-4 and IL-5 have moderate anti-tumor effects against 38C13 B cell lymphoma both in vivo and in vitro, and that the observed in vivo anti-tumor effects are probably mediated both by tumoristatic action of infiltrating cells, such as eosinophils, macrophages and T lymphocytes, and by direct anti-proliferative action of the recombinant cytokines.     

Anti-tumor effects of interleukin-2 and interleukin-1 in mice transplanted with different syngeneic tumors

We have studied the anti-tumor effects of human recombinant IL-2, alone or in association with LAK cells, in mice transplanted subcutaneously (s.c.) with the following syngeneic tumors: highly metastatic Friend leukemia cells (FLC), nonmetastatic FLC, lymphoma RBL-5 cells and HeJ16 fibrosarcoma cells. In these tumor models, peri-tumoral injections of IL-2 were more effective in inhibiting tumor growth than a systemic treatment. Although s.c. IL-2 treatment resulted in marked inhibition of tumor growth in mice injected s.c. with highly metastatic FLC, it was not effective in inhibiting growth of FLC in the liver and spleen. IL-2 therapy was more effective at increasing survival time in mice transplanted with non-metastatic FLC or with RBL-5 cells. In mice transplanted with HeJ16 fibrosarcomas, s.c. IL-2 treatment resulted in highly significant anti-tumor effect and survival of 70% of tumor-injected mice. No general correlation was found between in vitro sensitivity or resistance to the cytolytic activity of LAK cells and the anti-tumor effects observed in vivo. Subcutaneous injection of IL-1 beta in mice transplanted with highly metastatic FLC resulted in a marked increase in survival time and inhibition of metastatic tumor growth in liver and spleen. Combined treatment of IL-1 beta and IL-2 produced a synergistic anti-tumor effect: 60% of mice injected with highly metastatic FLC survived. Combined IL-1/IL-2 treatments exerted no anti-tumor activity either in DBA/2 mice injected with antibody to Thy 1.2 antigen or in nude mice, indicating that T cells play important roles during IL-1/IL-2 therapy. In vitro treatment of FLC with IL-1 beta resulted in a slight inhibition of cell multiplication, whereas even high doses of IL-2 did not affect FLC multiplication. Our results indicate that local combined treatments with IL-1 and IL-2 can induce potent, host-dependent (T cell-mediated) anti-tumor effects against highly malignant tumors.     

Antitumor Activity of Recombinant Human Interleukin-1 against Heterotransplanted Human Non-Hodgkin Lymphomas in Nude Mice

Antitumor activity of recombinant human interleukin 1α (IL-1) against seven human non-Hodgkin lymphomas grown in athymic nude mice was studied. Growth of the lymphomas was markedly inhibited after an injection of 0.4 mg/kg IL-1. The growth inhibition of Burkitt lymphoma was found to be dose-dependent up to 0.4 mg/kg, reaching a plateau thereafter. The loss of colony-forming ability of the cells and the loss of cell viability showed the same type of dose-dependence and progressed during 24 h following an injection of IL-1. In accordance with these observations, histopathologic examination revealed progressively spreading coagulative necrosis without bleeding. Little infiltration of inflammatory cells into the tumor tissue was observed. IL-1 growth inhibition of T lymphoma in beige nude mice having low natural killer activity was similar to that in nude mice. These findings suggested that the antitumor effects might not be produced through cell-mediated antitumor actions. Immunocytological examination with anti-IL-1 antibody revealed that administered IL-1 was bound to the lymphoma cells, suggesting that IL-1 receptor is probably expressed on these cells in vivo . The antitumor action of IL-1 on the lymphomas may be exerted directly through the IL-1 receptor.     

Rejection of Mouse Renal Cell Carcinoma Elicited by Local Secretion of Interleukin-2

We introduced the interleukin-2 (IL-2) gene into mouse renal cell carcinoma (RenCa) in order to examine the mechanism of tumor rejection. IL-2 gene-transfected RenCa (RenCa/IL-2Hi) exhibited marked retardation of tumor growth when implanted in a syngeneic host. Growth retardation of RenCa/IL-2Hi was also observed in athymic nude mice even after depletion of natural killer (NK) cells by treatment with anti-asialo GM1 antibody. Histological analysis of RenCa/IL-2Hi tumors disclosed non-specific inflammatory changes in syngeneic hosts. Co-injection of Bacillus Calmette Guerin with RenCa/IL-2Hi considerably enhanced the anti-tumor effects. Taken together, these findings strongly suggest that in situ IL-2 production leads to tumor rejection through non-specific inflammatory responses without participation of T cells and NK cells. On the other hand, the syngeneic mice that had rejected RenCa/IL-2Hi acquired immunity against parental RenCa, suggesting possible participation of memory T cells in the second rejection of the tumor.     

Combination therapy of murine liver cancer with il-12 gene and HSV-TK gene

Interleukin-12 (IL-12), produced by antigen-presenting cell, is a heterodimeric cytokine that has multiple immune regulatory functions, various studies have shown that IL-12 has multiple anti-tumor effects and anti-metastatic properties for many tumors.[1] Suicide gene approaches are also widely investigated recently, the gene products are capable of converting the non-toxic pro-drug to the active cytotoxic agent. The most commonly used suicide gene and pro-drug is the herpes simplex virus th…     

Antitumor Effector Mechanism of Interleukin-lβ at a Distant Site in the Double Grafted Tumor System

Recombinant human interleukin-lβ (IL-lβ) Inhibited the growth of not only the right, but also the left non-treated tumor in a double grafted tumor system. Since the antitumor activity of IL-lβ against the right and left tumors was not seen in nude mice, lymphocytes have a key role in the antitumor effect of intratumoral administration of IL-lβ. TIL (tumor-infiltrating leukocytes) obtained from left and right side tumors treated with IL-1β were examined by Winn assay for their antitumor activity against Meth-A sarcoma in BALB/c mice. TIL from the right side clearly inhibited the growth of admixed Meth-A cells, but control TIL did not. Spleen cells and right and left regional lymph node cells prepared from IL-1-treated mice were examined for Lyt-1, Lyt-2 and L3T4 phenotypes. The number of Lyt-1-positive lymphocytes increased in the spleen and in the right regional lymph nodes after intratumoral administration of IL-1. Isolated tumor cells obtained from the right tumor treated with IL-lβ and the left side tumor on day 6 were cultured in RPMI1640 with 10% fetal calf serum for 24 h. The culture supernatants were harvested and tested for the presence of chemotactic activity for neutrophils or macrophages. Significant neutrophil chemotactic factor and macrophage chemotactic factor activities were detected in the culture media from IL-1-treated tumor tissues cultured for 24 h. Neither significant neutrophil nor macrophage chemotactic activity was detected in the media from untreated tumor tissues. These results suggest that intratumoral administration of IL-1 first induces neutrophils and macrophages in the right tumor, then Lyt-1-positive cells in the right regional lymph nodes and in the spleen, and subsequently induces macrophages in the left, non-treated tumor.     

Interleukin-4 and breast cancer

IL-4 is a pleiotropic cytokine produced by T lymphocytes which acts on various cells of such as T and B lymphocytes, monocytes, fibroblast, endothelial cells, macrophages and some others. IL-4 was originally described as a B cell growth factor, and now known to provide potent anti-tumor activity against various tumors, including breast cancer. IL-4 can induce apoptosis in cultured breast cancer cells. In addition, it has been clarified that IL-4 plays an important role in the regulation of estrogen synthesis enzymes including 17beta-HSD and 3beta-HSD. These findings imply that IL-4 is a key enzyme not only for Th2 type immune reactions but also for tumor cell growth itself in human breast cancer.     

IL-27基因对Eca109细胞在裸鼠体内的成瘤抑制作用及其机制

背景与目的:细胞因子为主的肿瘤生物治疗已成为肿瘤研究领域热点之一。本研究观察白细胞介素(interleukin,IL)-27基因转染人食管癌Eca109细胞株后在裸鼠体内的成瘤抑制作用及其机制。方法:以逆转录病毒为载体,采用基因转染的方法用G418梯度筛选法建立转染IL-27基因的Eca109细胞,RT-PCR检测其基因导入情况,ELISA法检测IL-27的分泌和其诱导外周血单个核细胞(peripheral blood mononuclear cells,PBMC)产生γ-干扰素(interferon,IFN)的能力,MTT法观察Eca109/IL-27细胞生长情况。将Eca109/IL-27、Eca109/LXSN和Eca109细胞接种于裸鼠皮下,观察其成瘤性、移植瘤的生长情况并计算抑瘤率。流式细胞技术检测移植瘤组织肿瘤浸润淋巴细胞(tumor infiltrating lymphocyte,TIL)中CD16、FasL的表达和肿瘤细胞上Fas的表达。结果:RT-PCR示Eca109/IL-27细胞中有IL-27p28和IL-27EBI3亚基基因表达,Eca109/LXSN和Eca109细胞中未见表达(P<0.01),从而成功建立稳定转染的Eca109/IL-27细胞株,ELISA检测Eca109/IL-27中IL-27的分泌量高于Eca109/LXSN和Eca109细胞(P<0.01)。IL-27基因转染不影响人食管癌细胞株的体外生长(P>0.05),Eca109/IL-27诱导PBMC产生IFN-γ含量高于Eca109/LXSN和Eca109[(56.28±1.61)pg/mL vs.(12.70±0.82)pg/mL]和(11.06±0.64)pg/mL,P<0.01),Eca109/IL-27移植瘤体积较Eca109和Eca109/LXSN减小,瘤重减轻,有抑瘤作用(P<0.05);Eca109/IL-27细胞接种的肿瘤组织TIL中CD16阳性率升高,FasL的表达增高(P<0.05),肿瘤细胞表面Fas表达增加(P<0.05)。结论:IL-27基因修饰Eca109细胞在裸鼠体内产生了抑制肿瘤生长的作用,其机制可能是通过活化自然杀伤细胞,以Fas/FasL的途径产生的。     

Expansion of natural killer cells in mice transgenic for IgM antibody to ganglioside GD2: demonstration of prolonged survival after challenge with syngeneic tumor cells

IgM antibodies to gangliosides, sialic acid-containing glycosphingolipids, have been shown to mediate anti-tumor effects in cancer patients with melanoma and neuroblastoma and to correlate with survival. Mechanisms by which the antibodies induce tumor suppression, however, have not been systematically studied. To investigate this point, we produced and characterized C57BL/6 mice transgenic for IgM antibody to ganglioside GD2. The transgenic (TG) mice showed high IgM, but not IgG antibody titers against GD2 in their sera. No significant clinical symptoms were observed. When EL4 cells, syngeneic T lymphoma that express ganglioside GD2, were injected into TG mice, prolonged survival was observed. Complement-dependent cytotoxicity (CDC) of EL4 cells was mediated with TG mice sera. Neither antibody-dependent cellular cytotoxicity with their sera nor cytotoxic T lymphocyte activity to EL4 cells was shown in TG mice. Spleen lymphocytes from TG mice had increased numbers of natural killer (NK) cells, but not T cells, B cells, or macrophages compared with wild-type mice. Depletion of NK cells with anti-asialo GM1 rabbit serum reduced or abrogated the observed anti-tumor effects, suggesting that NK cells play a major role in tumor eradication or suppression. NK cell activity in TG mice was much higher than wild-type mice. Moreover, TG mice showed prolonged survival after injection with syngeneic B16 melanoma cells, which express GM3, but not GD2 or GD3. Taking these results together, our studies demonstrate that the TG mice have significant anti-tumor characteristics, probably due to CDC and NK cell expansion and activation with anti-ganglioside GD2 antibody.     

Nitric oxide accelerates interleukin-13 cytotoxin-mediated regression in head and neck cancer animal model.

Receptors for interleukin-13 (IL-13R) are overexpressed on several types of solid cancers including gliobastoma, renal cell carcinoma, AIDS Kaposi's sarcoma, and head and neck cancer. Recombinant fusion proteins IL-13 cytotoxin (IL13-PE38QQR or IL13-PE38) have been developed to directly target IL-13R-expressing cancer cells. Although it has been found that IL-13 cytotoxin has a direct potent antitumor activity in vivo in nude mice models of human cancers, the involvement of indirect antitumor effecter molecules such as nitric oxide (NO) is unknown. To address this issue, we assessed the effect of NO inhibiter N(omega)-monomethyl-l-arginine on IL-13 cytotoxin-mediated cytotoxicity and NO2/NO3 production in HN12 head and neck cancer cells. In addition, antitumor effects and NO levels in HN12 and KCCT873 head and neck tumors xenografted s.c. in nude mice when treated with IL-13 cytotoxin were evaluated by tumor measurement, Western blot, and immunohistochemistry analyses. Pretreatment of animals with N(omega)-monomethyl-l-arginine significantly decreased the NO levels and IL-13 cytotoxin-mediated antitumor effects. In addition, depletion of macrophages, known to produce NO, also decreased antitumor activity of IL-13 cytotoxin. Based on these studies, we concluded that NO accelerates antitumor effect of IL-13 cytotoxin on head and neck tumor cells. Because IL-13 cytotoxin is currently being tested in the clinic for the treatment of patients with recurrent glioblastoma maltiforme, our current findings suggest maintaining macrophage and NO-producing cellular function for optimal therapeutic effect of this targeted agent.     

Interleukin-7 Enhances the in Vivo Anti-tumor Activity of Tumor-reactive CD8+ T cells with Induction of IFN-gamma in a Murine Breast Cancer Model

Interleukin-7 (IL-7) is a potent anti-apoptotic cytokine that enhances immune effector cell functionsand is essential for lymphocyte survival. While it known to induce differentiation and proliferation in somehaematological malignancies, including certain types of leukaemias and lymphomas, little is known about itsrole in solid tumours, including breast cancer. In the current study, we investigated whether IL-7 could enhancethe in vivo antitumor activity of tumor-reactive CD8+ T cells with induction of IFN-γ in a murine breast cancermodel. Human IL-7 cDNA was constructed into the eukaryotic expression plasmid pcDNA3.1, and then therecombinational pcDNA3.1-IL-7 was intratumorally injected in the TM40D BALB/C mouse graft model. Serumand intracellular IFN-γ levels were measured by ELISA and flow cytometry, respectively. CD8+ T cell-mediatedcytotoxicity was analyzed using the MTT method. Our results showed that IL-7 administration significantlyinhibited tumor growth from day 15 after direct intratumoral injection of pcDNA3.1-IL-7. The anti-tumoreffect correlated with a marked increase in the level of IFN-γ and breast cancer cells-specific CTL cytotoxicity.In vitro cytotoxicity assays showed that IL-7-treatment could augment cytolytic activity of CD8+ T cells fromtumor bearing mice, while anti-IFN-γ blocked the function of CD8+ T cells, suggesting that IFN-γ mediated thecytolytic activity of CD8+ T cells. Furthermore, in vivo neutralization of CD8+ T lymphocytes by CD8 antibodiesreversed the antitumor benefit of IL-7. Thus, we demonstrated that IL-7 exerts anti-tumor activity mainly throughactivating CD8+ T cells and stimulating them to secrete IFN-γ in a murine breast tumor model. Based on theseresults, our study points to a potential novel way to treat breast cancer and may have important implicationsfor clinical immunotherapy.     

Interleukin-12 enhances the antitumor activity of cytotoxic T lymphocytes against lung adenocarcinoma engrafted in severe combined immunodeficient mice

Background. Through a number of biologic activities, interleukin 12 (IL-12) has proven to be a potential antitumor cytokine in mice bearing a variety of malignancies. However, in clinical trials in humans, the eradication of solid tumors remains difficult. Methods. A lung cancer cell line (PC-9)-specific cytotoxic T lymphocytes (CTL) were generated by multiple stimulations, with irradiated PC-9 cells, of regional lymph node lymphocytes obtained from patients with lung cancer whose cells expressed the same HLA-A locus haplotype as PC-9 (HLA-A24). Severe combined immunodeficient (SCID) mice bearing a subcutaneous graft of PC-9 were then intravenously injected with anti-PC-9-specific CTLs. Under these conditions, the in-vivo effect of recombinant human (rh) IL-2 and rh IL-12 was evaluated, based on tumor growth. Results. Mice that received either rh IL-2 or rh IL-12 exhibited no inhibitory effect on tumor growth. However, mice that received adoptive immunotherapy (AIT) alone exhibited a significant inhibition of tumor growth in the PC-9 graft in comparison to untreated mice. When mice were treated with AIT combined with rh IL-2 + rh IL-12 administration, tumor growth was significantly suppressed. A significant difference was observed in the growth of the PC-9 graft between AIT + IL-2 + IL-12 treatment and AIT + IL-2 treatment. Four of eight mice in the AIT + IL-2 + IL-12-treated group showed complete tumor regression. Conclusion. IL-12 showed a synergistic effect with adoptive immunotherapy, using CTL in a tumor-engrafted SCID model. These results are therefore considered to provide a sufficient rationale for IL-2 + IL-12-based immunotherapy using CTL transfer for patients with lung cancer. Received: June 30, 1999 / Accepted: May 10, 2000     

Macrophage Expression of Interleukin-1 in Lymphoepithelioid Cell (“Lennert's”) Lymphoma

Macrophage activation was studied in three cases of a genuine form of T cell non-Hodgkin's lymphoma particularly rich in epithelioid histiocytes, the so-called “lymphoepithelioid cell lymphoma” or “Lennert's lymphoma”. Host tumor infiltrating macrophages actively produced Interleukin-1 as demonstrated by immunocytochemistry. The activated histiocytes also contained intracytoplasmic tumor cells which were either intact or at various stages of apoptosis. We postulate that in Lennert's lymphoma, tumor cells are capable of activating host macrophages. Initial macrophage activation is followed by IL-1 production with recruitment of additional macrophages accounting for the characteristic histological appearance of this tumor. The activated macrophages are also engaged in a phagocytic antitumoral response. Future studies should investigate if this host response can be potentiated.     

Interleukin-13 Receptor-Directed Cytotoxin for Malignant Glioma Therapy: From Bench to Bedside

Central nervous system malignant neoplasias, in particular, glioblastoma multiforme (GBM) have defied all current therapeutic modalities. New therapies involving tumor targeting approach are being explored. This approach relies on the identification of unique or over-expressed cell surface receptors or antigens on tumor cells. In that regard, we have identified receptor for an immune regulatory cytokine, interleukin-13 (IL-13), which is over-expressed on human malignant glioma cell lines and primary tumor cell cultures. To target IL-13 receptors (IL-13R) for cancer therapy, we have developed a recombinant fusion protein composed of IL-13 and a mutated form of Pseudomonas exotoxin (IL13-PE38QQR or IL-13 cytotoxin). The IL-13 cytotoxin was found to be highly selective and potent in killing human GBM cells in vitro while normal cells including immune cells, endothelial cells and normal brain cells were generally spared the cytotoxic effect of IL-13 cytotoxin. This is because these cells either expressed none or expressed low levels of IL-13R.Consistent with in vitro cytotoxic activity, IL-13 cytotoxin mediated remarkable anti-tumor activity to human glioma in animal xenograft models. The direct injection of IL-13 cytotoxin into subcutaneous human GBM tumors grown in nude mice produced complete and durable regression of established tumors. Intravenous and intraperitoneal administration of IL-13 cytotoxin also reduced tumor burden significantly with fewer complete responders. All animals tolerated therapy well with minimal toxicity to vital organs. Pre-clinical safety and toxicity studies were performed in mice, rats and monkeys. Systemic administration of IL-13 cytotoxin appeared to be well tolerated at high doses (up to 50ug/kg). Intrabrain parenchyma administration of IL-13 cytotoxin at doses up to 100ug/ml was very well tolerated without any evidence of gross or microscopic necrosis, whereas at 500ug/ml dose, localized necrosis was observed in normal rat brain. Based on these encouraging pre-clinical studies, three Phase I/II clinical trials in adults with malignant glioma have been initiated. The first clinical trial involves convection-enhanced delivery (CED) of IL-13 cytotoxin into recurrent malignant glioma. This route of IL-13 cytotoxin administration appears to be fairly well tolerated with no neurotoxicity. The second clinical trial involves infusion of IL-13 cytotoxin by CED following tumor resection. The initial stage of the second study assessed histologic effect of drug administered prior to resection. In third one, IL-13 cytotoxin is infused by CED followed by tumor resection. All three clinical trials are currently ongoing.     

Interleukin-13-regulated M2 macrophages in combination with myeloid suppressor cells block immune surveillance against metastasis

CD1-deficient mice reject established, disseminated 4T1 metastatic mammary cancer and survive indefinitely if their primary mammary tumors are surgically removed. This highly effective immune surveillance is due to three interacting mechanisms: (a) the generation of inducible nitric oxide synthase (iNOS)-producing M1 macrophages that are tumoricidal for 4T1 tumor cells; (b) a rapid decrease in myeloid-derived Gr1(+)CD11b(+) suppressor cells that are elevated and down-regulate the CD3zeta chain when primary tumor is present and that suppress T cells by producing arginase; and (c) production of activated lymphocytes. Macrophages from wild-type BALB/c mice are polarized by interleukin-13 (IL-13) towards a tumor-promoting M2 phenotype, thereby inhibiting the generation of tumoricidal M1 macrophages. In contrast, CD1(-/-) mice, which are deficient for IL-13 because they lack IL-13-producting NKT cells, generate M1 macrophages that are cytotoxic for 4T1 via the production of nitric oxide. Although tumoricidal macrophages are a necessary component of immune surveillance in CD1(-/-) mice, they alone are not sufficient for tumor resistance because IL-4Ralpha(-/-) mice have M1 macrophages and retain high levels of myeloid suppressor cells after surgery; in addition, they are susceptible to 4T1 metastatic disease. These results show that effective immune surveillance against established metastatic disease is negatively regulated by IL-13 and requires the induction of tumoricidal M1 macrophages and lymphocytes combined with a reduction in tumor-induced myeloid suppressor cells.     

白细胞介素21的免疫调节功能及其在血液肿瘤中的作用

白细胞介素21(IL-21)作为新的免疫系统调节因子, 在免疫调节、抗肿瘤中的作用已经成为近年来的研究热点。白细胞介素21受体(IL-2lR)表达在大多数的淋巴细胞, 对多种免疫细胞, 包括B淋巴细胞、T淋巴细胞、NK细胞和树突状细胞都有重要的生物调节作用, 进而在宿主抗肿瘤免疫和许多癌症的免疫治疗中具有一定作用。许多研究已经证实IL-21对于多种恶性肿瘤发挥良好的抗肿瘤作用, 并且部分已应用于临床。新近的研究表明, IL-21对于不同的血液肿瘤具有不同的作用, 如对B细胞慢性淋巴细胞白血病、非霍奇金淋巴瘤和白血病, 其可以发挥抗肿瘤作用, 此作用机制包括直接抗肿瘤作用及通过作用于免疫细胞发挥间接的抗肿瘤作用。而对于霍奇金淋巴瘤和多发性骨髓瘤则表现为促进肿瘤细胞的生长, 其作用机制包括通过激活相应的信号途径和作用于相应的细胞因子。本文对IL-21的免疫调节功能及其在血液肿瘤中的相关研究进行综述。      

Helper strategy in tumor immunology: Expansion of helper lymphocytes and utilization of helper lymphokines for experimental and clinical immunotherapy

Two main kinds of immune strategy are possible against neoplasia. The first potentiates a selected effector arm. In vitro culture with exogenous interleukin-2 (IL-2) increases the activity of natural killer cells and leads to the expansion of T cytotoxic lymphocytes. Systemic reinfusion of both of these cells with high doses of IL-2 mediates the regression of a variety of murine and human tumors. In an alternative strategy, a few regulatory lymphocytes turn on immune reactivity by triggering a cascade of interconnected effector functions. The efficacy of this strategy rests on the repertoire of effector mechanisms moved to action. An effective immunoregulatory maneuver is the addition of helper determinants on the surface of tumor cells. Its power can be further increased by the pre-induction of helper T lymphocytes specific to the helper determinants. This approach can be achieved in mice by coupling muramyl dipeptides to tumor cells, along with eliciting T lymphocytes specifically reactive to Bacillus Calmette-Guerin. Noncytotoxic T helper lymphocytes produce factors which recruit nonspecific (macrophages) as well as specific (cytolytic T lymphocytes) anti-tumor attacking cells. In this way protection can be afforded against primary tumors and metastases, as well as leukemia cells. As the activity of helper lymphocytes rests mostly on lymphokine release, the use of molecularly defined lymphokines mimicking T-helper functions has also been attempted. In a few experimental models, the association of low doses of IL-2 with non-reactive lymphocytes from tumor-bearing mice promotes an effective anti-tumor reaction in the host. Moreover, the combination of distinct lymphokines can also build a molecularly defined helper system able to activate in sequence non-specific and specific anti-tumor reactions in vivo. Trials intended to evaluate the clinical impact of these helper approaches in the management of human tumors are being started or are already under way.     

Antitumor Effect of Interleukin-1β in the Double Grafted Tumor System

The antimetastatic effect of recombinant human interleukin-1β (rIL-1β) in a new experimental mouse model was studied. Intratumoral administration of IL-1β strongly inhibited the growth of Meth-A solid tumors in male BALB/c mice and led to a complete regression of tumors and resistance to reinoculated tumor. Subsequently, the anti-metastatic effect of IL-1β was examined in the double grafted tumor system, in which mice first received simultaneous intradermal inoculations of Meth-A in both right (10⁶ cells) and left (2×10⁵ cells) flanks and were then injected with 0.2 μg of IL-1β in the right tumor on days 3, 4 and 5. IL-1β significantly inhibited the growth of the left, non-treated tumor. When mice received only an inoculation of Meth-A (2×10⁵ cells) in the left flank and were injected subcutaneously with IL-1β into the right flank on day 3 (single tumor system), there was no inhibition of the growth of the left, non-treated tumor. These findings suggest that intratumoral IL-1β immunotherapy in one region has an effect on tumor growth in another region. Immunized spleen cells were taken from mice which had been cured by the intratumoral administration of IL-1β. Adoptive transfer of the immunized spleen cells caused the complete regression of Meth-A tumors. These results suggest that intratumoral administration of IL-1β might induce cytotoxic cells in the left non-treated tumor of the double grafted tumor system and bring about the regression of metastatic tumors. On the other hand, recombinant tumor necrosis factor was effective only on the treated, right tumor, having no effect on the distant, left tumor in the double grafted tumor system. Recombinant interleukin-2 was effective on neither the right tumor nor the left tumor in this system. These results show that there are major differences of antitumor mechanism among cytokines.     

转GM-CSF基因瘤苗联合IL-12治疗T细胞淋巴瘤的实验研究

目的　探讨用转粒细胞巨噬细胞 集落刺激因子 (GM CSF)基因瘤苗 ,联合白介素 12 (IL 12 )治疗小鼠T细胞淋巴瘤的方法。方法　将小鼠GM CSF真核表达质粒 ,用电穿孔法导入小鼠T细胞淋巴瘤细胞系RMA ,有限稀释法制备单个细胞克隆 ,经RT PCR、骨髓祖细胞增殖实验和集落形成实验 ,筛选相对高表达GM CSF的RMA克隆 ,该克隆细胞用丝裂霉素灭活后免疫小鼠 ,以诱导产生抵抗RMA肿瘤细胞再攻击的能力 ,并观察其与IL 12联合应用对淋巴瘤的治疗作用。结果　获得了高表达GM CSF的小鼠T细胞淋巴瘤克隆 ,其动物体内致瘤活性降低 ,将其用丝裂霉素灭活后作为瘤苗可使小鼠产生抗肿瘤的免疫保护力 ,与IL 12联合应用增强其抗肿瘤活性。结论　转GM CSF基因瘤苗可作为有效的抗肿瘤瘤苗 ,与IL 12联合应用较其单独应用更为有效     

白细胞介素-18基因转染的肺癌细胞与树突状细胞融合体的抗肿瘤作用

目的研究白细胞介素-18(IL-18)基因转染的肺癌细胞与树突状细胞(DC)融合体的抗肿瘤作用。方法(1)从人外周血单核细胞诱导培养DC,与IL-18基因转染的NCI-H460肺癌细胞融合,经免疫磁珠筛选。(2)设转染组(GT组)、空载体转染组(PT组)、未转染组(NT组)和对照组(BC组),分别以IL-18转染的融合细胞、pcDNA3.1~ 转染的融合细胞、未转染的融合细胞活化的T细胞为效应细胞,BC组不含效应细胞,用乳酸脱氢酶(LDH)法测定效应细胞对NCI-H460细胞的杀伤作用。(3)荷瘤裸鼠皮下注射上述3种效应细胞,以BC组为空白对照,比较4组裸鼠肿瘤体积和重量。结果3组效应细胞在体外对NCI-H460细胞的杀伤率分别为53.1%,30.1%和31.5%;3组裸鼠肿瘤体积及肿瘤重量明显低于BC组,以GT组最低。结论IL-18基因转染的融合细胞可有效诱导抗肿瘤免疫。