Intravenous administration of MIP-1alpha with intra-tumor injection of P. acnes shows potent anti-tumor effect

Dendritic cells (DCs) play a key role as potent biological adjuvants in anti-tumor host responses. However, DC-based vaccination does not always eradicate tumors effectively. Clinical evidence suggests that a strategy to recruit a substantial number of DCs into the tumor mass might provoke proficient anti-tumor immune responses. Here we describe that myeloid DCs (mDCs) efficiently accumulate in tumor sites after intravenous injection of recombinant macrophage inflammatory protein (MIP)-1alpha when pretreated locally with adjuvants like Propionibacterium acnes. Combined treatment of tumor-bearing mice with MIP-1alpha and P. acnes also recruited a large number of natural killer cells (NK cells) to both tumor sites and regional lymph nodes (LNs) and induced a strong T helper 1 immunity at an early time. This early response later led to accumulation of CD8(+) T cells, retraction of tumors and survival of animals treated with P. acnes/MIP-1alpha. In vivo depletion of NK cells or CD8(+) T cells impaired anti-tumor effects, suggesting that activation of NK cells and CD8(+) T cells contributes to anti-tumor immunity in this model. Therefore, this study provides a novel therapeutic strategy for cancer treatment using MIP-1alpha and certain adjuvants.     

Combined administration of the apoptin gene and poly (I:C) induces potent anti-tumor immune response and inhibits growth of mouse mammary tumors

BackgroundMany viral proteins exhibit selective cytotoxicity for tumor cells without affecting the normal diploid cells. The apoptin protein of chicken infectious anemia virus is one of such proteins, which has been shown to kill tumor cells specifically. However, an effective cancer treatment strategy also requires assistance from the immune system. Recently, poly (I:C) has been shown to be an effective cancer vaccine adjuvant.AimIn this study, we assessed the anti-tumor potential of apoptin gene transfer alone and in combination with poly (I:C) in a 4T1 mouse mammary tumor model.Methods4T1 cells were used to induce mammary tumor in Balb/c mice. Mice bearing tumors were divided into 6 groups, and each group received six intratumoral injections during a period of one month. After the last immunization, the animals were sacrificed, and peripheral blood, spleen, lungs, liver, heart, kidney and tumor tissues were collected for immunological, molecular and pathological analysis.ResultsWe report that intratumoral administration of apoptin plasmid along with poly (I:C) not only significantly inhibited the growth of mammary tumor, but also induced a potent anti-tumor immune response as indicated by the increase in blood CD4 +, CD8 + cells and infiltration of immune cells in the tumor tissue. Further, blood serum analysis of the cytokines revealed increased secretion of Th1 cytokines (IFN-γ and IL-2).ConclusionsThe results of our study demonstrate that the inclusion of poly (I:C) significantly enhanced the anti-tumor activity of apoptin mainly by inducing a potent anti-tumor immune response. Therefore, we report the use of apoptin and poly (I:C) combination as a novel and powerful strategy for cancer immunotherapy.     

Procyanidin,a kind of biological flavonoid,induces protective anti-tumor immunity and protects mice from lethal B16F10 challenge

Recently, increasing evidences show that procyanidin (PC) modulate immune responses in human. To evaluate adjuvant effects of PC on vaccine immune modulation and anti-tumor activity, we formulated PC with B16F10 tumor antigen as tumor vaccine to immune C57BL/6 mice and used intramuscular injection before challenge with tumor B16F10 cells. Our results revealed that PC enhanced T cell-mediated immune responses both in vitro and in vivo. Moreover, the B16F10 tumor vaccine induced some degree of anti-tumor effects as evaluated by the inhibition of tumor growth and the prolongation of survival. The tumor-bearing mice showed a high level of specific cytotoxic activity and had activated CD8 T cells that secreted perforin, IFN-γ and TNF-α in response to the stimulation with antigen in vitro. Taken together, current study presents evidence that PC may be used as a promising vaccine adjuvant.     

抗CD40抗体增强宫颈癌肽疫苗的治疗作用

目的：探讨抗CD40抗体对宫颈癌肽疫苗治疗作用的影响。方法将乳头状病毒结构性蛋白 E7表位肽（ E749－57,H－2Db限制性,CD8 T细胞表位）与Toll样受体7配体（Gardiquimod）组成疫苗,C57BL／6小鼠给予疫苗及抗CD40抗体免疫后取得外周血及脾组织CD8 T细胞,利用流式细胞仪分析特异性CD8 T细胞数量,Elisa检测CD8 T细胞与TC－1细胞（表达HPV E7蛋白的小鼠宫颈癌细胞）共孵育后干扰素（ INF－γ）表达水平。另取15只皮下荷瘤小鼠,监测免疫后肿瘤生长速度。结果与单用疫苗组相比,抗 CD40抗体明显增加小鼠外周血肿瘤特异性 CD8 T细胞数量（16．50±0．8185％ vs 9．747±1．834％,P＝0．0282）,且内源性CD8 T细胞体外与TC－1细胞共孵育可以分泌INF－γ,体内显著抑制皮下肿瘤生长（ P＜0．001）。结论抗CD40抗体增强肽疫苗诱发的免疫应答,有潜力成为一种良好的佐剂。     

A novel cyclic peptide targeting LAG-3 for cancer immunotherapy by activating antigen-specific CD8+ T cell responses

PD-1 and CTLA-4 antibodies offer great hope for cancer immunotherapy. However, many patients are incapable of responding to PD-1 and CTLA-4 blockade and show low response rates due to insufficient immune activation. The combination of checkpoint blockers has been proposed to increase the response rates. Besides, antibody drugs have disadvantages such as inclined to cause immune-related adverse events and infiltration problems. In this study, we developed a cyclic peptide C25 by using Ph.D.-C7C phage display technology targeting LAG-3. As a result, C25 showed a relative high affinity with human LAG-3 protein and could effectively interfere the binding between LAG-3 and HLA-DR (MHC-II). Additionally, C25 could significantly stimulate CD8⁺ T cell activation in human PBMCs. The results also demonstrated that C25 could inhibit tumor growth of CT26, B16 and B16-OVA bearing mice, and the infiltration of CD8⁺ T cells was significantly increased while FOXP3⁺ Tregs significantly decreased in the tumor site. Furthermore, the secretion of IFN-γ by CD8⁺ T cells in spleen, draining lymph nodes and especially in the tumors was promoted. Simultaneously, we exploited T cells depletion models to study the anti-tumor mechanisms for C25 peptide, and the results combined with MTT assay confirmed that C25 exerted anti-tumor effects via CD8⁺ T cells but not direct killing. In conclusion, cyclic peptide C25 provides a rationale for targeting the immune checkpoint, by blockade of LAG-3/HLA-DR interaction in order to enhance anti-tumor immunity, and C25 may provide an alternative for cancer immunotherapy besides antibody drugs.     

NY-ESO-1/HSP65融合蛋白腹腔免疫小鼠的免疫效果

目的  观察NY-ESO-1/热休克蛋白65（heat shock protein 65,HSP65）融合蛋白（NY-H）免疫BALB/c小鼠诱导的体液和细胞免疫应答及其抗肿瘤作用。 方法  将BALB/c小鼠按简单随机方法分组,分别用 NY-H、NY-ESO-1与HSP65混合（NY+H）、NY-ESO-1、HSP65和PBS腹腔免疫4次,间隔2周。每次免疫后第14天,对小鼠尾静脉采血,检测血清抗体滴度。末次免疫后第7天,取小鼠脾细胞,检测细胞因子、淋巴细胞增殖水平、CD4+和CD8+ T细胞的百分比及对肿瘤细胞的特异性杀伤作用,采用t检验或2检验对结果进行比较。结果 NY-H组小鼠在第1次免疫后就产生了较高水平的抗体（吸光度值为0.841±0.059）,与NY+H组（0.333±0.077）和NY-ESO-1组（0.275±0.183）相比差异有统计学意义（t=12.753,P<0.01;t=7.204,P<0.01）。NY-H组小鼠的IL-2和IFN-γ分泌能力均高于其他各组,并且CD4+、CD8+ T细胞数量大幅增高,细胞增殖率（38.00%±3.84%）明显高于NY+H组（12.90%±0.65%）和NY-ESO-1组（10.90%±1.44%）（x=830.1,P<0.01;x²=994.0,P<0.01)。小鼠免疫NY-H后,脾淋巴细胞能特异性杀伤表达NY-ESO-1的小鼠B16肿瘤细胞。 结论  NY-H能诱导小鼠产生较强的体液和细胞免疫应答,且具有良好的抗肿瘤作用。     

Immunotherapy with tumor-targeted superantigens (TTS) in combination with docetaxel results in synergistic anti-tumor effects

In this study we explored the possibility of combining immunotherapy against cancer with the well-established cytostatic drug docetaxel. Tumor-targeted superantigens (TTS) utilizes the powerful T cell activating property of a superantigen such as staphylococcal enterotoxin A (SEA) in fusion with an anti-tumor Fab-fragment to target this T cell activity against tumor cells. TTS fusion proteins are efficient in a number of experimental tumor models including the B16 mouse melanoma transfected with a human tumor-associated antigen (GA733-2 or EpCam) recognized by the C215 monoclonal antibody. The distinct mechanisms of action of TTS and docetaxel provide the prerequisites for successful combination treatment. However, as a result of the anti-proliferative properties of cytostatic drugs, chemotherapy may modify TTS induced immune activation during combination treatment.Here we evaluated the anti-tumor effects of combining C215Fab-SEA with docetaxel against B16-C215 tumors growing in the lung of C57Bl/6 mice. Both compounds generated a significant reduction in the number of B16-C215 lung tumors when administered alone. Prior treatment with docetaxel at therapeutic doses did not interfere with superantigen induced T cell activation but rather appeared to enhance the response, while simultaneous treatment was suppressive. Combining TTS and docetaxel significantly improved tumor therapy, further reducing the number of lung tumors as compared to mono therapies. Importantly, the combination treatment at timely settings synergistically prolonged long term survival in B16-C215 tumor bearing mice. The results of this study demonstrate that TTS immunotherapy is highly compatible with docetaxel and suggest a significant potential of the combination for human cancer therapy.     

Learning from Viruses: The Necrotic Bodies of Tumor Cells with Intracellular Synthetic dsRNA Induced Strong Anti-tumor Immune Responses

Purpose Coaxing dead tumor cells to induce specific immune responses is an attractive tumor therapy. However, there continues to be a need for adjuvants that can promote the cross-presentation of the dead tumor cells to induce specific anti-tumor response. Viral dsRNA has multiple mechanisms to promote the cross-presentation of viral antigens in virus-infected cells. We propose to learn from viruses by generating dead tumor cells having synthetic dsRNA delivered inside them to allow the dsRNA to promote the cross-presentation of dead tumor cells. Materials and Methods Using synthetic dsRNA, poly(I:C), and the TC-1 cervical cancer model, we evaluated the extent to which the poly(I:C) can promote the necrotic bodies of TC-1 cells to induce specific anti-tumor immune response. The poly(I:C) was either simply mixed with the dead TC-1 cells or pre-loaded inside them. Results Immunization of tumor-bearing mice with the necrotic bodies of tumor cells admixed with poly(I:C) significantly inhibited the tumor growth. More importantly, immunization with the necrotic bodies having poly(I:C) pre-loaded inside led to a significantly stronger anti-tumor response than when the necrotic bodies were simply admixed with the poly(I:C), apparently through a CD8⁺ CTL response-mediated mechanism. Conclusions These findings are expected to be clinically relevant for devising improved whole cell-based tumor vaccines.     

Combining tumor-targeted superantigens with interferon-alpha results in synergistic anti-tumor effects

In this study we explored the possibility of improving the anti-tumor potency of tumor-targeted superantigens (TTS) by combination treatment with interferon-alpha (IFN-alpha). TTS utilizes the powerful T cell activating property of the superantigen staphylococcal enterotoxin A (SEA) in fusion with an anti-tumor Fab-fragment to target this T cell activity against tumor cells. TTS fusion proteins have shown anti-tumor efficacy in a number of experimental tumor models including the B16 mouse melanoma transfected with a human tumor-associated antigen recognized by the C215 monoclonal antibody. IFN-alpha is approved for the treatment of solid tumors such as renal cell carcinoma and malignant melanoma and exerts immunomodulatory effects, which make it an appropriate candidate to combine with immunotherapy against cancer. Here we report that daily administration of IFN-alpha (20 000 U i.p.) enhances and sustains CD8+ T cell activation induced by the TTS C215Fab-SEA (10 microg i.v.) in C57Bl/6 mice, as reflected by increased and prolonged cell-mediated cytotoxicity against tumor cells ex vivo as well as by augmented serum IFN-gamma levels. C215Fab-SEA synergized with IFN-alpha in reducing the number of lung tumors in B16-C215 melanoma bearing mice as compared to mono therapy. In a long term tumor survival experiment, the prolonged median survival time of the combination treatment was 3.5 and 7.7 times the prolonged median survival times of C215Fab-SEA and IFN-alpha monotherapies, respectively. Hence, the combination treatment provoked synergistic anti-tumor effects as measured by the number of lung tumors and markedly prolonged survival. The enhanced therapeutic efficacy correlated with a striking and sustained increase of CD8- and perforin-expressing tumor-infiltrating cells. These results suggest significant potential of combining TTS with IFN-alpha for human cancer therapy.     

Low-dose curcumin leads to the inhibition of tumor growth via enhancing CTL-mediated antitumor immunity

Curcumin, a yellow pigment extracted from turmeric, is widely used to inhibit tumor progression. Since it can either promote or suppress the immune system, how curcumin affects the immune system in tumor-bearing bodies is not yet clear. Our study found that tumor-bearing mice treated consecutively once a day with low-dose curcumin for ten days led to a retarded tumor growth and a longer survival, which might be contributed to T cell-mediated adaptive immune response. The in vitro study also showed that a high-dose curcumin decreases T cells whereas a low-dose increases T cells derived from 3LL tumor-bearing mice, especially CD8+ T cells. Accordingly, these increased CD8+ T cells exhibited the enhancement of IFN-γ secretion, proliferation and cytotoxicity specifically against 3LL tumor cells, which may result in the success of antitumor immunity. Our research demonstrated a beneficial effect of curcumin on CD8+ T cells derived from tumor-bearing mice, which can provide a potential application in anti-tumor therapy.     

Involvement of doxorubicin-induced Fas expression in the antitumor effect of doxorubicin on Lewis lung carcinoma in vivo

Deficiency of Fas expression is one of mechanisms involved in the immune evasion by tumors. Several antitumor drugs, such as doxorubicin (DOX) increase Fas expression in tumor cells and sensitize the cells to Fas-mediated apoptosis in vitro. However, the significance of the Fas expression in vivo is still unclear. Therefore, we examined a role of Fas expression on antitumor effect of DOX using a syngeneic tumor model of Lewis lung carcinoma (3LL) cells in C57BL/6-gld mice that lack functional Fas ligand (FasL). In vitro, anti-Fas agonistic antibody, Jo2, did not decrease a viable cell number of 3LL cells in the absence of DOX, whereas it significantly reduced the cell viability in the presence of DOX. The treatment with DOX alone at the same dose did not induce cell death. Flowcytometric analysis of Fas expression revealed that 3LL cells expressed only a marginal amount of Fas, but the treatment of the cells with DOX increased the expression of Fas in the cell surface. When splenic T cells were prepared from 3LL-bearing C57BL/6 mice, the splenic T cells significantly killed DOX-pretreated 3LL cells more than untreated 3LL cells. In the syngeneic models, DOX inhibited growth of 3LL solid tumor both in wild-type C57BL/6 mice and in Fas-deficient C57BL/6-lpr mice, but it failed in C57BL/6-gld mice, suggesting that the interaction between host FasL and tumor Fas is involved in the antitumor effect of DOX. Furthermore, Fas expression was increased in the solid tumor by the treatment of DOX. These results suggest that the antitumor effect of DOX is partly exerted by the Fas expression and host immune defense.     

Host mediated anti-tumor effect of Nocardia rubra cell wall skeleton on syngeneic tumor in mice

The mode of action of Nocardia rubra cell wall skeleton (N-CWS) on Meth A fibrosarcoma (Meth A) was studied in BALB/c mice. N-CWS suppressed or regressed the intradermal growth of syngeneic Meth A cells in normal BALB/c and athymic BALB/c mice. The intradermally and subcutaneously infiltrated cells harvested from injection sites of N-CWS in normal mice showed in vitro cytotoxic activity against Meth A cells. Pretreatment of normal BALB/c mice with immunosuppressing agents such as hydrocortisone, carrageenan, or silica particles significantly reduced the anti-tumor effect of N-CWS. The growth of Meth A cells, rechallenged into BALB/c mice in which Meth A cells had once been suppressed or regressed by N-CWS treatment, was also inhibited, but not in similarly treated athymic nude mice. This resistant mechanism was shown to be dependent out cellular components but not on humoral components by the Winn Assay. The present results suggest that N-CWS exerts its anti-tumor activity by mediation of the immune system of the host and that the main effector cells in the early stage of tumor rejection are macrophages; T cells may also be involved in the later stage.     

Curdlan activates dendritic cells through dectin-1 and toll-like receptor 4 signaling

Curdlan, a β-1,3-glucan isolated from Alcaligenes faecalis, is an agonist of dectin-1 in various immune cells, including dendritic cells (DCs). However, whether curdlan also activates DCs through other receptors remains unknown. In this study, we found that curdlan activates DCs through dectin-1 and toll-like receptor 4 (TLR4). Curdlan increased the expression levels of surface molecules (CD40, CD80, CD86, and MHC-I/II), the production of cytokines (IL-12, IL-1β, TNF-α, and IFN-β), migration toward MIP-3β, and allogeneic T cell stimulation activity of DCs. Curdlan increased the phosphorylation of Syk, Raf-1, Akt, MAPKs, IKK, and NF-κB p65 in DCs. However, curdlan only slightly activated DCs transfected with small interfering RNAs against dectin-1 or TLR4 and C3H/HeJ DCs, which have non-functional TLR4, in comparison with control DCs. Curdlan increased antitumor activity of DCs in a syngeneic tumor model. In summary, our data show that curdlan activates DCs through dectin-1 and TLR4 signaling and the combination of curdlan and DCs efficiently inhibit tumor growth in mice.     

Carcinoembryonic antigen as a target to induce anti-tumor immune responses

Identification of relevant targets for cancer therapy is a major goal in cancer research. In this field, the identification of tumor antigens has opened the possibility of inducing specific anti-tumor immune responses. Among these antigens, carcinoembryonic antigen (CEA) is especially relevant because CEA is expressed in a wide variety of adenocarcinomas such as colon, rectum, pancreas, gastric, breast, etc. The present review focuses on different strategies to induce anti-CEA immune responses. In a first group of strategies, the antigen is administered using viral and bacterial vectors expressing CEA, dendritic cells loaded with CEA protein, or dendritic cells transfected with DNA or RNA expressing CEA. A second group of strategies is based on immunizations with antigenic peptide determinants from CEA, rather than with immunogens containing the whole protein. This has been possible due to the identification of different peptide determinants from CEA, which when presented by MHC class I molecules, are recognized by T cytotoxic lymphocytes. More recently, due to the importance of CD4(+) T cells in the induction of immune responses, T helper peptides presented by MHC class II molecules have also been identified. To overcome the poor immunogenicity of CEA-derived peptide determinants, a common feature of self-antigens, their sequence has been modified to improve binding to MHC molecules or recognition by T cell receptors. Finally, in order to enhance immunization efficacy, some of these strategies have combined the administration of immunogens and cytokines or co-stimulatory molecules. Some of the immunization protocols developed are being tested in clinical trials with promising results. Thus, CEA may prove to be a valuable target antigen for the therapy of a high number of malignancies.     

反义胰岛素样生长因子—1mRNA治疗大鼠脑胶质瘤模型的动态MR研究

目的：动态观察大鼠Ｃ６胶质瘤模型的自然生长过程及反义ＩＧＦ－１ｍＲＮＡ对胶质瘤的治疗效果和治疗机制。方法：将３２只Ｗｉｓｔａｒ大鼠分成４组,每组８只,（１）对照组（Ｃ组）于右尾状核接种Ｃ６鼠胶质瘤细胞。（２）治疗组（Ｔ组）：于右尾状核接种Ｃ６细胞后的第７、１０天在接种点注射脂质体包裹的质粒Ｐ－ａｎｔｉ－ＩＧＦ－１,对胶质瘤进行治疗于右尾状核接种经反义ＩＧＦ－１ｍＲＮＡ转染的Ｃ６胶质瘤细胞。（４）Ｋ     

Effects of methionine enkephalin on immune enhancement by reducing myeloid derived suppressor cells and reprogramming liver metabolism in colon cancer mice

OBJECTIVE To investigate enhanced immune function of methionine encephalin(MENK)and its anti-tumor mechanism in CT26 colon cancer mouse model.METHODS 3×10~6CT26 cells were implanted subcutaneously in BALB/c mice.Four days after,MENK was peritoneally administrated at the concentration of 20 mg·kg~(-1) for 14 d.The percentage of MDSCs in bone marrow,spleen,blood,tumor and liver were detected by flow cytometry.Non-esterified fatty acid(NEFA),triglycerides(TG)and total cholesterol(T-CHO)in liver homogenate were tested by a NEFA test kit,a TG test kit and a T-CHO test kit respectively.qRT-PCR and Western blot were used to measure m RNA and protein levels of inflammation-,glycometabolsim-and lipometabolsim-associated indexes in liver.RESULTS MENK decreased percentages of MDSCs in bone marrow,spleen,blood and tumor in colon cancer mice.MENK-treated mice displayed elevated ratio of CD4~+T and CD8~+T cells in spleen as well as increased T and B lymphocytes proliferation.Meanwhile,MENK also ameliorated liver damage reflected by lower levels of GPT and GOT in serum and reduced risks of cancer-associated index including inflammation,high lipid and high glucose.Furthermore,MENK lowered down the levels of NEFA,TG and T-CHO in liver homogenate.MENK treatment decreased expression of p-STAT3,increased expression of p-AKT,IRS1 and Glut4 at protein level as well as reduced lipogenesis-associated genes and elevated glycolysis-associated genes in liver of tumor bearing mice.Also,abated expression of genes associated with MDSCs generation(M-CSF,GM-CSF,IL-6,IL~(-1)β)and migration(S100A9,KC)was observed within shrunken subcutaneous tumor by MENK intervention.CONCLUSION MENK has the ability to strength immune function against colon cancer by reducing MDSCs and improving liver metabolism.     

Resveratrol analog, HS-1793 enhance anti-tumor immunity by reducing the CD4+CD25+ regulatory T cells in FM3A tumor bearing mice

Natural agents with the immunomodulating property have been gaining traction to be employed in the complementary therapy of cancer because the ineffectiveness of numerous therapeutic strategies may be related in part to the tumor-induced immunosuppressive phenotypes, especially regulatory T (Treg) cells found in the tumor microenvironment. The present study was undertaken to examine whether HS-1793, synthetic resvertrol analog free from the restriction of metabolic instability and high dose requirement of resveratrol, induces an in vivo anti-tumor effect in FM3A tumor bearing mice through the suppression of Treg cells, which contribute to an increase in tumor specific cytotoxic T cell responses. Intraperitoneal injections of HS-1793 showed not only therapeutic benefits on established tumors, but also preventive anti-tumor effects. Treg cells (CD4+CD25+Foxp3+ cells) were significantly reduced in the total splenocytes as well as tumor tissues from HS-1793-administered mice, and the production of TGF-β inducing Treg showed a similar pattern. On the contrary, the administration of HS-1793 increased IFN-γ-expressing CD8+ T cells, upregulated IFN-γ production, and enhanced the cytotoxicity of splenocytes against FM3A tumor cells both in therapeutic and preventive experimental animals. These results demonstrated the suppressive role of HS-1793 on the function of Treg cells contributing to tumor specific cytotoxic T lymphocyte responses in tumor-bearing mice, which explained the underlying mechanism of the anti-tumor immunity of HS-1793.     

Pathogenesis of Murine Coronavirus in the Central Nervous System

Murine coronavirus (mouse hepatitis virus, MHV) is a collection of strains that induce disease in several organ systems of mice. Infection with neurotropic strains JHM and A59 causes acute encephalitis, and in survivors, chronic demyelination, the latter of which serves as an animal model for multiple sclerosis. The MHV receptor is a carcinoembryonic antigen-related cell adhesion molecule, CEACAM1a; paradoxically, CEACAM1a is poorly expressed in the central nervous system (CNS), leading to speculation of an additional receptor. Comparison of highly neurovirulent JHM isolates with less virulent variants and the weakly neurovirulent A59 strain, combined with the use of reverse genetics, has allowed mapping of pathogenic properties to individual viral genes. The spike protein, responsible for viral entry, is a major determinant of tropism and virulence. Other viral proteins, both structural and nonstructural, also contribute to pathogenesis in the CNS. Studies of host responses to MHV indicate that both innate and adaptive responses are crucial to antiviral defense. Type I interferon is essential to prevent very early mortality after infection. CD8 T cells, with the help of CD4 T cells, are crucial for viral clearance during acute disease and persist in the CNS during chronic disease. B cells are necessary to prevent reactivation of virus in the CNS following clearance of acute infection. Despite advances in understanding of coronavirus pathogenesis, questions remain regarding the mechanisms of viral entry and spread in cell types expressing low levels of receptor, as well as the unique interplay between virus and the host immune system during acute and chronic disease.     

重组腺病毒mCD40L联合5-Fu治疗小鼠腹腔肿瘤的研究

目的 探讨重组腺病毒鼠CD40配体基因(Ad-mCD40L)对小鼠CT26腹腔肿瘤的治疗作用.方法 建立小鼠CT26腹腔肿瘤动物模型,检测腺病毒介导的鼠CD40配体基因联合5-Fu对肿瘤生长的抑制作用.结果 腹腔内灌注Ad-mCD40L+5-Fu,可明显抑制CT26肿瘤结节的生长.Ad-mCD40L能激发小鼠特异的免疫反应,增强诱导肿瘤细胞凋亡的作用,抑制肿瘤细胞的增殖.结论 Ad-mCD40L联合5-Fu可产生更强的抗肿瘤效应,为结肠癌的生物-化疗提供了新的思路.