MUC1 and survivin combination tumor gene vaccine generates specific immune responses and anti-tumor effects in a murine melanoma model

MUC1 and survivin are ideal tumor antigens. Although many cancer vaccines targeting survivin or MUC1 have entered clinical trials, no vaccine combining MUC1 and survivin have been reported. Due to tumor heterogeneity, vaccines containing a combination of antigens may have improved efficacy and coverage of a broader spectrum of cancer targets. Here, cellular responses and anti-tumor activities induced by a combination of DNA vaccine targeting MUC1 and survivin (MS) were evaluated. Results showed that CTL activity and inhibition of tumor growth were obviously enhanced in mice immunized with the combined vaccine in a protection assay. However, in order to enhance the therapeutic effect in the treatment assay, a recombinant adenovirus (rAd) vaccine expressing MUC1 and survivin (Ad-MS) was used as a booster following the DNA vaccine prime. Meanwhile, IL-2 promoting T cell proliferation was used as an immunoadjuvant for the DNA vaccine. Results showed that the CTL activity response to the DNA vaccine was enhanced nearly 200% when boosted by the rAd vaccine and was further enhanced by nearly 60% when combined with the IL-2 adjuvant. Therefore, DNA prime combined with rAd boost and IL-2 (MS/IL2/Ad-MS) adjuvant was considered as the best strategy and further evaluated. Multiple cytokines promoting cellular immune responses were shown to be greatly enhanced in mice immunized with MS/IL2/Ad-MS. Moreover, in the treatment assay, the tumor inhibition rate of MS/IL2/Ad-MS reached up to 50.1%, which may be attributed to the enhancement of immune responses and reduction of immunosuppressive factors in tumor-bearing mice. These results suggested that immunization with the combination vaccine targeting MUC1 and survivin using a DNA prime–rAd boost strategy along with IL-2 adjuvant may be an effective method for breaking through immune tolerance to tumors expressing these antigens with potential therapeutic benefits in melanoma cancer.     

Co-immunization with plasmid IL-12 generates a strong T-cell memory response in mice

Plasmid encoded exogenous IL-12 delivered as a DNA vaccine adjuvant has been shown to improve vaccine-induced immunity. In particular, pIL-12 greatly improves antigen (Ag)-specific cytotoxic tlymphocyte (CTL) activity in immunized mice. The longevity of this response has not previously been studied in detail. We have studied the effect of co-immunization with pIL-12 on HIV gp160 and Influenza A Hemeagglutinnin-specific memory immune responses. Mice co-immunized with pIL-12 and plasmid encoded antigens maintained a greater memory response than those immunized with the plasmid antigen alone which could be measured at least 6 months after vaccination. Further, this translated to an improved outcome after challenge of long term rested mice that were previously immunized. The strength of the immune response as well as the number of Ag-specific T-cells is proportional to the number of Ag-specific cells primed by the vaccination regimen.     

SST-2 tumor inoculation is a useful model for studying the anti-tumor immune response in SHR rats

Objective The purpose of the present study was to investigate the relation between the dose of tumor cell inoculation (especially the doses less than minimum required to evoke tumor growth) and the anti-tumor immune system, particularly lymphoblast formation and cytotoxic activity of lymphcytes. Method We inoculated rats with various doses of SST-2 tumor cells and examined natural killer (NK) cell activity and lymphoblast formationin vitro. Result The results showed that the cytotoxicities against SST-2 cells and lymphoblast formation of lymphocytes were enhanced by small dose inoculation of tumor cells that could not induce tumor growth. Conclusion It was suggested that was lymphocutes play an important role as an anti-tumor immune system at small doses of tumor inoculation, which appears to reflect an early stage of tumor growthin vivo. It was also suggested that SST-2 tumor inoculation might be a useful model for studying the anti-tumor immune response in SHR rats.     

A MUC1/IL-18 DNA vaccine induces anti-tumor immunity and increased survival in MUC1 transgenic mice

MUC1 (mucin 1) is a tumor-associated antigen that is overexpressed in many adenocarcinomas. Active immunotherapy targeting tumors expressing MUC1 could have great treatment value. MUC1 DNA vaccines were evaluated in MUC1 transgenic (MUC1.Tg) mice challenged with MC38/MUC1+ tumor cells. Vaccination with MUC1 plasmid DNA (pMUC1) alone was insufficient to induce tumor protection. However, co-administration of pMUC1 with a plasmid encoding murine interleukin-18 (pmuIL-18) resulted in significant tumor protection and survival after tumor challenge. Protection was durable in the absence of additional vaccination, as demonstrated by continued protection of vaccinated mice following tumor rechallenge. Mice surviving challenges with MC38/MUC1+ cells showed significant protection after challenge with MUC1(-) MC38 tumor cells, suggesting that these mice had developed immune responses to epitopes shared between the tumor cell lines. Antibody-mediated depletion of lymphocyte subsets demonstrated that protection was due largely to CD4+ T cells. This work demonstrates that a naked DNA vaccine can break tolerance to MUC1 and induce an immune response capable of mediating both significant protection from tumor challenge and increased survival.     

Antitumor efficacy of MUC1-derived variable epitope library treatments in a mouse model of breast cancer

The identification of novel targets for cancer immunotherapy and the development of new vaccine immunogens are subjects of permanent interest. MUC1 is an overexpressed antigen found in most tumors, and its overexpression correlates with poor prognosis. Many attempts to direct the immune response against MUC1 in tumor cells have failed, including several clinical trials. We have previously developed an innovative Variable Epitope Library (VEL) vaccine platform that carries massively substituted mutant variants of defined epitopes or epitope regions as an alternative to using wild-type peptide sequences-based immunogens. Here, two murine MUC1-derived epitopes equivalent to the previously tested in cancer immunotherapy human MUC1 regions were used to generate VELs. We observed that vaccination with the 23L VEL immunogens, encompassing the entire signal peptide region of MUC1, reduces the tumor area compared to the wild-type sequence treatment. Contrastingly, vaccination with the MUC1 signal peptide-derived predicted CD8⁺+ T cell epitope-based VEL, 9MUC1spL, showed similar tumor area reduction as the wild-type treatment; however, a decrease in lung metastasis after 9MUC1spL treatment was observed. In addition, vaccination induced a large pool of CD8⁺ T cells which recognized most variant epitopes from 9MUC1spL. Also, we generated MUC1 variable number tandem repeat (VNTR)-based VELs that reduced the metastatic burden when dendritic cells and M13 recombinant bacteriophages were used as vaccine carriers. Collectively, our data demonstrate the immunogenic and antitumor properties of MUC1 signal peptide- and VNTR-derived VEL immunogens.     

Estrogen replacement therapy and colon cancer: a clinical review

Colorectal cancer is the third leading cause of cancer death in women. Studies on the potential protective effect of postmenopausal hormone replacement on the incidence of colon cancer have been contradictory. To attempt to clarify the potential protective effect of hormone replacement therapy (HRT), an English-language key word (KW) search of MEDLINE, up to August 1999, was performed for KW colon cancer or colorectal adenoma or colon adenoma or adenomatous polyp and KW estrogen replacement or hormone replacement. Additional references were obtained from reading of the reference lists. Thirty-five studies, including 3 meta-analyses, were found. Of these, 23 suggested any degree of protective effect of HRT, 11 reported neutral results, and 1 reported negative impact of hormone replacement. The single prospective randomized controlled trial included small numbers of inpatients taking high-dose estrogen. However, studies did not uniformly specify hormone type, dose, duration, and potential differential effects on right and left colon. Estrogen and progesterone effects were not often considered separately. Many studies had inadequate control of confounders, for example, family history of colon cancer or indication for endoscopy. Therefore, although the majority of studies, especially more rigorously designed recent studies, support the conclusion that postmenopausal estrogen replacement therapy (ERT) has a protective effect against colon adenomas and colon cancer, methodological limitations preclude practical application of study results at present. Prospective studies are needed to confirm the existence and degree of protective effect, as well as to specify the mechanism of protection.     

Heterologous prime-boost vaccination with a non-replicative vaccinia recombinant vector expressing LACK confers protection against canine visceral leishmaniasis with a predominant Th1-specific immune response

Leishmaniasis caused by Leishmania infantum is a severe endemic disease in the Mediterranean basin, being domestic dogs the main reservoir of the disease that plays a key role in the transmission to humans. Studies on vaccines against canine leishmaniasis, aimed to modify the T cell repertoire, have advanced in recent years. LACK vaccination assays, using protein or DNA vectors, show protection against cutaneous L. major infections by redirecting the early IL-4 responses to a protective Th1 response. The aim of this study was to define the effectiveness and type of immune response in a canine visceral leishmaniasis model of two poxvirus vectors (Western reserve strain, WR and modified vaccinia virus Ankara, MVA) expressing the LACK protein of L. infantum in prime/boost vaccination protocols. The results obtained showed that dog vaccination priming with DNA-LACK followed by a booster with MVA-LACK or rVV-LACK triggered a Th1 type of immune response, leading to protection against canine visceral leishmaniasis. This protection correlated with absence of visceral leishmaniasis symptoms, lower Leishmania-specific antibodies, higher degree of T cell activation in Leishmania-target organs and higher synthesis of Th1 cytokines. In addition, we found that dogs boosted with the non-replicative virus show less VL symptoms and higher degree of T cell activation, providing evidences for a clear advantage of MVA-LACK as a vaccination vector against canine visceral leishmaniasis.     

IL-18 potentiates the adjuvant properties of IL-12 in the induction of a strong Th1 type immune response against a recombinant antigen

Due to the synergistic effects of IL-12 and IL-18, and to their importance in establishing a Th1 type immune response, we investigated the potential of a combined administration of both cytokines as an adjuvant for recombinant antigens. As a model system, we used a schistosome T cell antigen recently identified in our group. By co-adsorption of this antigen on alum in the presence of IL-12 and IL-18, we demonstrate that IL-18 enhances the effects of IL-12 in inducing an antigen-specific Th1 type CD4(+) T cell response as well as high titres of IgG1, IgG2a, and IgG2b antibodies.     

免疫营养素应用于肿瘤治疗的研究进展

免疫营养素在营养支持、调节免疫和维护肠黏膜屏障功能等方面有着重要的作用。近年来,随着研究的不断深入,免疫营养素在肿瘤综合治疗中发挥的重要作用不断被人们所认识。许多研究表明,谷氨酰胺(Gln)、多不饱和脂肪酸(PUFA)和精氨酸(Arg)对肿瘤本身及肿瘤联合化疗均有着重要的作用。     

Applying a stage model of behavior change to colon cancer screening

BACKGROUND: There has been limited use of stages of change models in characterizing colorectal cancer (CRC) screening. We assess the applicability of the Precaution Adoption Model (PAPM) by determining the distribution of stages of adoption and by elucidating differences among stages. METHODS: The study is based on 1394 responses (69%) to a survey mailed in 2002 to patients in a primary care population. Survey measures included: self-reported CRC screening, sociodemographic characteristics, health system characteristics, attitudes and beliefs about CRC screening, perceived vulnerability to CRC, and worry about CRC. The main outcome was PAPM stage of adoption of CRC screening based on the ACS preferred guidelines: colonoscopy every 10 years alone or the combination annual FOBT plus sigmoidoscopy every 5 years. RESULTS: 57% were up-to-date with at least one test; 36% were up-to-date with the ACS preferred guidelines; provider recommendation, positive family history of CRC, and positive decisional balance score were significantly associated with higher compared to lower PAPM stages. CONCLUSIONS: The combination of PAPM stage assignment and other factors provides useful information for designing tailored interventions. There are special challenges in developing and interpreting PAPM stage assignments when a guideline offers multiple pathways to adherence and recommends a combination of two tests as a preferred option.     

Dendritic cells transfected with PEG10 recombinant adenovirus elicit anti-tumor immune response in vitro and in vivo

Recent evidence demonstrates that PEG10 plays an essential role in hepatocarcinogenesis and development, thus it could be regarded as a therapeutical target for hepatocellular carcinoma (HCC). In addition, transduction with recombinant, replication-defective adenoviral (Ad) vectors encoding tumor associated antigen into dendritic cells (DCs) is an efficient strategy to elicit antigen specific cytotoxic T lymphocytes (CTLs) for cancer therapy. In the present study, DCs were transduced with the PEG10 recombinant adenovirus, and were utilized to elicit CTLs in vitro.Moreover, the Trimera mice were immunized with the transduced DCs to elicit the immune response, the tumor growth and the life span of tumor bearing mice were observed. The results demonstrated that the transduced DCs could effectively induce specific CTL response against HCC without lysing autologous lymphocytes, but also significantly inhibit the tumor growth and prolong the life span of tumor bearing mice. These data suggest that PEG10 recombinant adenovirus transduced DCs can induce anti-tumor immunity against HCC expressing PEG10 in vitro and in vivo. Thus, the transduction of DCs with Ad-PEG10 provides a promising strategy for cancer immunotherapy of HCC.     

Vaccination with the Mycoplasma suis recombinant adhesion protein MSG1 elicits a strong immune response but fails to induce protection in pigs

Mycoplasma suis is the unculturable pathogen of porcine infectious anemia. The study was aimed to determine the immunogenicity and protective efficacy of MSG1, an immunodominant adhesin of M. suis as the first vaccine candidate against M. suis. The results demonstrated that recombinant MSG1 and Escherichia coli transformants expressing MSG1 (E. coli_MSG1) induced a strong humoral and cellular immunity against M. suis. The induced antibodies were found to be functionally active as confirmed by an in vitro adhesion inhibition assay. Both, IgG1 and IgG2 antibodies were induced, but E. coli_MSG1 immune response was characterized by a significantly higher IgG1 antibody production. Both vaccine candidates failed to protect against M. suis challenge. However, E. coli_MSG1 vaccination has a considerable effect on the severity of the disease as shown by higher post-challenge hemoglobin and hematocrit values in comparison to control groups. This indicated that a high IgG1 antibody titer is negatively connected with severity of M. suis-induced anemia. Furthermore, the induction of monospecific anti-MSG1 antibodies by both vaccine candidates clearly allows for the differentiation between infected and vaccinated animals (DIVA principle). Overall, the importance of MSG1 as potential vaccine candidate remains to be established. Future studies will evaluate the conditions (i.e. adjuvant, vaccination scheme, and application route) to optimize the effects of E. coli_MSG1 vaccines.     

Sequential administration of a MVA-based MUC1 cancer vaccine and the TLR9 ligand Litenimod (Li28) improves local immune defense against tumors

TG4010 is an immunotherapeutic vaccine based on Modified Vaccinia virus Ankara (MVA) encoding the human tumor-associated antigen MUC1 and human IL-2. In combination with first-line standard of care chemotherapy in advanced metastatic non-small-cell lung cancer (NSCLC), repeated subcutaneous injection of TG4010 improved progression-free survival in phase 2b clinical trials. In preclinical tumor models, MVATG9931, the research version of TG4010, conferred antigen-specific responses against the weak antigen human MUC1. The combination of a suboptimal dose of MVATG9931 and the type B TLR9 ligand Litenimod (Li28) markedly increased survival in a subcutaneous RMA-MUC1 tumor model compared to the treatment with MVATG9931 or Li28 alone. The requirements for this protection were (i) de novo synthesis of MUC1, (ii) Li28 delivered several hours after MVATG9931 at the same site, (iii) at least two vaccination cycles, and (iv) implantation of MUC1-positive tumor cells in the vicinity to the vaccination site. Subcutaneously injected MVATG9931 allowed transient local gene expression and induced the local accumulation of MCP-1, RANTES, M-CSF, IL-15/IL-15R and IP-10. After repeated injection, CD4⁺ and CD8⁺ T lymphocytes, B lymphocytes, NK cells, pDCs, neutrophils, and macrophages accumulated around the injection site, local RANTES levels remained high. Delayed injection of Li28 into this environment, led to further accumulation of macrophages, the secretion of IL-18 and IL-1 beta, and an increase of the percentage of activated CD69⁺ NK cell. Combination treatment augmented the number of activated CD86⁺ DCs in the draining lymph nodes and increased the percentage of KLRG1⁺ CD127⁻CD8⁺ T cells at the injection site. In vivo depletion of macrophages around the injection site by Clodronate liposomes reduced local IL-18 levels and diminished survival rates significantly. Thus, sequential administration of MVATG9931 and Li28 improves local innate and adaptive immune defense against tumors, arguing for intratumoral delivery of this peculiar sequential combination therapy.     

A novel Salmonella Typhi-based immunotherapy promotes tumor killing via an antitumor Th1-type cellular immune response and neutrophil activation in a mouse model of breast cancer

We investigated the use of a live, attenuated Salmonella enterica serovar Typhi vaccine strain as an antitumor immunotherapy. Mice bearing a subcutaneous tumor (LM3 mammary adenocarcinoma) were immunized on three occasions with S. Typhi strain CVD 915 by injection into the tumor, the peritumoral tissue and the draining lymph node areas; this procedure was termed Salmonella multiple treatment (Salmonella MT). Tumor-bearing mice subjected to the Salmonella MT exhibited reduced tumor growth, prolonged survival and reduced incidence of lung metastases, compared to untreated mice. We examined the mechanisms mediating this effect and found that Salmonella MT promoted an antitumor Th1-type response characterized by increased frequencies of IFN-γ-secreting CD4⁺ T and CD8⁺ T cells with reduction of regulatory T cells in tumor draining lymph nodes. The main cells infiltrating bacteria-treated tumors were activated neutrophils, which can exert an antitumor effect through the secretion of TNF-α. These results demonstrate for the first time the efficacy of an attenuated S. Typhi vaccine strain as a cancer immunotherapeutic agent. By potentiating the host antitumor immune response, this approach could be a powerful adjunct tool for cancer therapy.     

Evidence of a cross-protective immune response to influenza A in the cotton rat model

Epidemiologic evidence suggests that cross-protective immune responses to influenza A viruses that have different hemagglutinin and neuraminidase subtypes occur in humans. This study characterized this heterosubtypic immunity in cotton rats (Sigmodon hispidus). Animals were infected with influenza A/PR/8/34 (H1N1) or A/Wuhan/359/95 (H3N2), and then challenged with A/Wuhan/359/95(H3N2) virus 4 weeks later. Viral titers, respiratory rates, and pathology of the respiratory tract following primary and secondary infection were compared. Cross-protection from heterosubtypic influenza A challenge in cotton rats was characterized by enhanced viral clearance, protection from tachypnea, a vigorous early cellular recall response, and a reduction in bronchiolar epithelial cell damage. Cross-protection was retained in steroid treated animals, in which the inflammatory recall response was minimal. Identification of the mechanisms that contribute to cross-protection in cotton rats may lead to the development of influenza vaccine strategies that are broadly protective.     

A truncated HCV core protein elicits a potent immune response with a strong participation of cellular immunity components in mice.

The immunogenicity of a truncated HCV core protein (Co.120) was studied in BALB/c and C57BL/6 mice, given three intramuscular injections of antigen, adjuvanted with either aluminum hydroxide or Freund's adjuvant. A rapid antibody response was noted after the first dose, with both strains of mice eventually exhibiting comparable levels of anti-core IgG (titers >1:100000), with a mixed IgG1/IgG2a subclass response. Spleen cells from Co.120-immunized mice gave a significant specific proliferative response. IFN-gamma gene expression was also detected after an ex-vivo specific stimulation of spleen cells in all immunized mice. This response was independent of dose, H-2 genetic background or type of adjuvant. The results indicated that immunization with the Co.120 protein elicits a potent anti-HCV humoral and cellular immune response.     

Vaccination of newborn mice induces a strong protective immune response against respiratory and genital challenges with Chlamydia trachomatis

Chlamydia trachomatis infections can occur early in life and may result in long-term sequelae. To assess the feasibility of implementing a vaccine in newborns, groups of 2-day-old BALB/c mice were immunized intranasally (i.n.) with 1x10(4) inclusion forming units (IFU) of C. trachomatis mouse pneumonitis (MoPn). As a control, newborn mice were sham-immunized i.n. with minimal essential medium. In the vaccinated animals, strong Chlamydia-specific humoral and cell-mediated immune responses were observed. Six weeks after immunization, mice were challenged with MoPn i.n. or intravaginally (i.vag.). For the i.n. challenge, mice were inoculated with 10(4) or 10(5)IFU of MoPn per mouse, and in the case of the i.vag. challenge, each animal received 10(6)IFU. By day 10 post-infection (p.i.), the vaccinated mice challenged i.n. with 10(4)IFU, had gained an average of 6.7+/-1% of their body weight. In contrast, the sham-immunized mice had lost 14.9+/-1% of their weight (P<0.05). The mean number of IFU/lungs in the vaccinated animals was 800+/-300, while for the sham-immunized mice was 211+/-49x10(6) (P<0.05). Significant differences between the Chlamydia-vaccinated and the sham-immunized mice were also found in the groups challenged with 10(5)IFU. In the mice challenged i.vag., a significant decrease in the number of mice with positive cultures, and the intensity and duration of vaginal shedding was noted in the vaccinated mice compared to the sham-immunized mice (P<0.05). In conclusion, these results indicate that vaccination of neonatal mice can result in a protective response against a subsequent pulmonary or genital challenge with Chlamydia.     

Helicobacter pylori lipopolysaccharide promotes a Th1 type immune response in immunized mice

Helicobacter pylori (H. pylori) infection is prevalent worldwide and results in chronic gastritis, which may lead to peptic ulcer disease or gastric cancer. The goal of this study was to determine the role that H. pylori lipopolysaccharide (LPS) plays in stimulating host immune responses in the context of a vaccine. We compared H. pylori SS1 sonicate (LPS+) to a sonicate depleted of LPS (LPS-) in immunized BALB/c mice. Na?ve splenocytes produced high levels of TNF-alpha and IL-10 after incubation with LPS+ sonicate, while cells incubated with LPS- sonicate did not. Mice immunized with LPS+ sonicate developed a prominent innate response characterized by increased TNF-alpha and IL-10, as well as a strong antigen specific Th1 response including, IFN-gamma, IL-2 and high IgG2a serum titers. Mice that received LPS- sonicate were strongly Th2 biased in their immune response, with significantly more IL-4 than IFN-gamma and serum IgG1 titers higher than IgG2a. Together these studies suggest that H. pylori LPS in a whole cell sonicate vaccine promotes a Th1 immune response that may aid in protection or clearance of H. pylori infection.