Irradiated Vaccine Research Articles

Immunogenicity and protective efficacy of irradiated Salmonella Gallinarum against homologous challenge infection in Bovans brown chickens

Fowl typhoid is a systemic poultry disease caused by Salmonella Gallinarum (SG). It is responsible for significant economic loss, due to its severe morbidity and mortality. An irradiated vaccine is one of the possible alternatives to prevent and control fowl typhoid. This study aimed to evaluate the safety, immunogenicity, and protective efficacy of irradiated SG using a randomized control trial in chicken. A field strain of SG was exposed to different doses of gamma irradiation to determine its effect on the viability of SG. Safety and immunogenicity were assessed by administering irradiated SG orally to 3 groups (5 each) of 5 weeks old Bovans brown chickens at 2400, 2500, and 2600 gray (Gy). The protective efficacy of 108colony forming units (CFU) of SG irradiated at 2400 Gy administered orally and subcutaneously was then evaluated using homologous challenge infection and compared with SG 9R commercial vaccine using 40, 5-week old Bovans brown chickens where the chickens were randomly assigned to 4 groups. Chickens in Group 1were exposed to 108 CFU of irradiated SG orally; Group 2 to the same dose subcutaneously; Group 3 to SG 9R strain commercial vaccine subcutaneously, Group 4 to phosphate-buffered saline (PBS) orally. Data related to survival, antibody response, and pathological lesions were recorded. Mann-Whitney U-test, Kruskal-Wallis test, and Fisher’s exact tests were used to examine for statistical significance. Irradiation at 2600 Gy caused complete inactivation of SG whereas SG exposed to 2400 Gy showed better immunogenicity and was safe for chickens. Antibody response in a group of chickens vaccinated with irradiated SG administered subcutaneously (SC) was significantly higher than those vaccinated with the SG 9R vaccine on day 7 (p=0.003) and day 14 (p=0.002) post-immunization. Comparative evaluation of the protective efficacy based on the mortality rate of chickens after challenge showed that 2400 Gy irradiated SG vaccine administered SC and SG 9R vaccine-induced equal protection of 50% while the irradiated vaccine administered orally protected only 10% of chickens against homologous challenge infection. SG was not isolated from the liver, spleen, and feces of chickens that survived challenge infection until the end of the experiment. Irradiated SG administered SC is shown to be a promising vaccine against fowl typhoid. Further studies using a large sample size involving tuning of irradiation dose to improve immunogenicity and use of booster vaccination are recommended.
 Keywords: Chicken; Fowl typhoid; Gamma irradiation; Salmonella Gallinarum; Vaccine

A Peptide-Based PD1 Antagonist Enhances T-Cell Priming and Efficacy of a Prophylactic Malaria Vaccine and Promotes Survival in a Lethal Malaria Model.

The blockade of programmed cell death-1 (PD1) and its ligand PDL1 has been proven to be a successful immunotherapy against several cancers. Similar to cancer, PD1 contributes to the establishment of several chronic infectious diseases, including malaria. While monoclonal antibodies (mAbs) targeting checkpoint receptors are revolutionary in cancer treatment, the immune-related adverse events (irAEs) may prevent their utilization in prophylactic and therapeutic treatments of infectious diseases. The irAEs are, in part, due to the prolonged half-life of mAbs resulting in prolonged activation of the immune system. As an alternative modality to mAbs, peptides represent a viable option because they possess a shorter pharmacokinetic half-life and offer more formulation and delivery options. Here, we report on a 22-amino acid immunomodulatory peptide, LD01, derived from a Bacillus bacteria. When combined prophylactically with an adenovirus-based or irradiated sporozoite-based malaria vaccine, LD01 significantly enhanced antigen-specific CD8+ T cell expansion. Therapeutically, LD01 treatment of mice infected with a lethal malaria strain resulted in survival that was associated with lower numbers of FOXP3+Tbet+CD4+ regulatory T cells. Taken together, our results demonstrate that LD01 is a potent immunomodulator that acts upon the adaptive immune system to stimulate T cell responses both prophylactically and therapeutically.

Oxidized mitochondrial DNA sensing by STING signaling promotes the antitumor effect of an irradiated immunogenic cancer cell vaccine

Exposure to ionizing radiation, a physical treatment that inactivates live tumor cells, has been extensively applied to enhance the antitumor responses induced by cancer cell vaccines in both animal research and human clinical trials. However, the mechanisms by which irradiated cells function as immunogenic tumor vaccines and induce effective antitumor responses have not been fully explored. Here, we demonstrate that oxidized mitochondrial DNA (mtDNA) and stimulator of interferon genes (STING) signaling play a key roles in the enhanced antitumor effect achieved with an irradiated tumor cell vaccine. Elevations in ROS and oxidized mtDNA 8-OHG content could be induced in irradiated tumor cells. Oxidized mtDNA derived from irradiated tumor cells gained access to the cytosol of dendritic cells (DCs). Oxidized mtDNA, as a DAMP or adjuvant, activated the STING-TBK1-IRF3-IFN-β pathway in DCs, which subsequently cross-presented irradiated tumor cell-derived antigens to CD8+ T cells and elicited antitumor immunity. The results of our study provide insight into the mechanism by which an irradiated cell vaccine mediates antitumor immunity, which may have implications for new strategies to improve the efficacy of irradiated vaccines.

Neoantigen-based EpiGVAX vaccine initiates antitumor immunity in colorectal cancer.

Metastatic colorectal cancer (CRC) is poorly immunogenic, with limited neoantigens that can be targeted by cancer vaccine. Previous approaches to upregulate neoantigen have had limited success. In this study, we investigated the role of a DNA methyltransferase inhibitor (DNMTi), 5-aza-2'-deoxycytidine (DAC), in inducing cancer testis antigen (CTA) expression and evaluated the antitumor efficacy of a combinatorial approach with an epigenetically regulated cancer vaccine EpiGVAX and DAC. A murine model of metastatic CRC treated with combination therapy with an irradiated whole-cell CRC vaccine (GVAX) and DAC was used to assess the antitumor efficacy. DAC significantly induced expression of CTAs in CRC, including a new CTA Tra-P1A with a known neoepitope, P1A. Epigenetically modified EpiGVAX with DAC improved survival outcomes of GVAX. Using the epigenetically regulated antigen Tra-P1A as an example, our study suggests that the improved efficacy of EpiGVAX with DAC may due in part to the enhanced antigen-specific antitumor immune responses. This study shows that epigenetic therapy with DNMTi can not only induce new CTA expression but may also sensitize tumor cells for immunotherapy. Neoantigen-based EpiGVAX combined with DAC can improve the antitumor efficacy of GVAX by inducing antigen-specific antitumor T cell responses to epigenetically regulated proteins.

Evaluation of Immune Responses and Histopathological Effects against Gamma Irradiated Avian Influenza (Sub type H9N2) Vaccine on Broiler Chicken

Abstract Vaccination is a good strategy for the prevention of avian influenza virus. In this research Gamma Irradiated Avian Influenza (Sub type H9N2) Vaccine (GAIV) was prepared by 30 kGy irradiation and used for vaccination of broiler chickens. The purpose was a comparison of immune responses in the two routes of administration for the GAIV vaccine; intranasal and subcutaneously, use of Montanide ISA70 and Trehalose accompanied with irradiated vaccine and compare with formalin vaccine. The Influenza Virus A/Chicken/IRN/Ghazvin/2001/H9N2 was irradiated and used for vaccine formulation, and formalin inactivated AIV was used as conventional vaccine. Chickens were vaccinated by GAIV with and without Trehalose, GAIV and formalin vaccines with ISA70, two routes of administration were intranasal and subcutaneously. All the vaccinated chickens showed a significant increase in antibody titration. The most significant increase of antibody titration was in irradiated vaccine plus Trehalose groups intranasal and subcutaneously. After the first and second intranasal vaccination, the amount of IFN-gamma increased in the irradiated vaccine plus Trehalose group compared to other groups. However, most of the vaccinated groups did not show any significant increase of IFN-α concentration. Histopathological examination revealed lymphocyte infiltration (++), foci dispersed of hemorrhage and edema in intranasal vaccination groups and in addition to these, thickening of alveolar septa was observed in the injection groups. GAIV vaccine can be a good candidate for vaccine preparation, and Trehalose as a stabilizer protects viral antigenic proteins, also makes more absorbance of antigen by the inhalation route. In vaccinated chickens the ulcers in injected vaccines were lower than intranasal vaccines.

Irradiated lactic acid-stimulated tumour cells promote the antitumour immunity as a therapeutic vaccine.

Low pH and lactate accumulation are characteristic features of the tumour microenvironment. With our study finding that high concentrations of lactic acid can inhibit tumour growth, it is conceivable that the administration of lactic acid could promote antitumour immunity in the context of a tumour vaccine. To test this concept, we studied the antitumour effect of irradiated tumour cells stimulated with lactic acid in mouse xenograft models to potentially improve whole-cell tumour vaccines. In this study, we found that the effects of lactic acid-stimulated tumour cells on dendritic cells (DCs) included enhancing phagocytic function and stimulating maturation and aggregation. Moreover, lactic acid could potentiate the immunogenicity of an irradiated whole-tumour cell vaccine and thus inhibit tumour growth. We further verified that the antitumour immune response was mediated by CD8+ T cells. In addition, interferon-γ-expressing CD4+ and CD8+ T cell numbers increased in the spleen and lymph nodes of mice immunized with the irradiated lactic acid-stimulated cells. Furthermore, changes in the tumour microenvironment were also observed in this study. Our findings may be helpful for developing a new strategy for cancer therapy.

Dissecting the Stromal Signaling and Regulation of Myeloid Cells and Memory Effector T Cells in Pancreatic Cancer.

Myeloid cells are a prominent immunosuppressive component within the stroma of pancreatic ductal adenocarcinoma (PDAC). Previously, targeting myeloid cells has had limited success. Here, we sought to target the myeloid cells through modifying a specific stromal component. A murine model of metastatic PDAC treated with an irradiated whole-cell PDAC vaccine and PDAC specimens from patients treated with the same type of vaccine were used to assess the immune-modulating effect of stromal hyaluronan (HA) degradation by PEGPH20. Targeting stroma by degrading HA with PEGPH20 in combination with vaccine decreases CXCL12/CXCR4/CCR7 immunosuppressive signaling axis expression in cancer-associated fibroblasts, myeloid, and CD8+ T cells, respectively. This corresponds with increased CCR7- effector memory T-cell infiltration, an increase in tumor-specific IFNγ, and improved survival. In the stroma of human PDACs treated with the same vaccine, decreased stromal CXCR4 expression significantly correlated with decreased HA and increased cytotoxic activities, suggesting CXCR4 is an important therapeutic target. This study represents the first to dissect signaling cascades following PDAC stroma remodeling via HA depletion, suggesting this not only overcomes a physical barrier for immune cell trafficking, but alters myeloid function leading to downstream selective increases in effector memory T-cell infiltration and antitumor activity.

OC-8722 THE GENERATION AND TESTING OF A GENETICALLY ATTENUATED MALARIA PARASITE (GAP) VACCINE

BackgroundImmunisation with radiation-attenuated Plasmodium falciparum sporozoites (SPZ) (Sanaria PfSPZ Vaccine) can protect >90% of vaccinees against controlled human malaria infection (CHMI) and protects against naturally-transmitted P. falciparum in Africa for at least 6 months. Immunisation with sporozoites of genetically attenuated parasites (GAPs), which completely arrest after liver-cell invasion can be potentially safer and more potent than irradiated sporozoite vaccines. As part of a collaboration between two Dutch research groups (LUMC and Radboud University) and the US company, Sanaria, we describe the generation and first-in-man testing of a GAP vaccine,MethodsWe screened single and multiple gene deletion parasites in order to identify parasites that can invade hepatocytes but are unable to complete liver-stage development. Informed by rodent studies we created P. falciparum double gene-deletion mutant, Δb9Δslarp; sporozoites of this line were infective to human hepatocytes in vitro and to humanised mice but they completely arrest after invasion. PfΔslarpΔb9 PfSPZ (Sanaria PfSPZ-GA1 Vaccine) was manufactured in compliance with cGMPs and released for human clinical trials in the EU under a conditional release GMO license. This GAP vaccine was used to perform phase I (safety) and phase 2a (efficacy) clinical CHMI trial in the Netherlands.ResultsIn a dose escalating phase I clinical trial, the vaccine showed an excellent safety profile. All adverse events related to the vaccine were mild (grade 1). Based on this indication of safety, vaccine efficacy was examined by CHMI; 48 subjects were subsequently enrolled into phase 2a study and were immunised with either PfSPZ-GA1 or PfSPZ Vaccine or saline placebo.ConclusionsIn conclusion, PfSPZ-GA1 Vaccine is the first injectable genetically attenuated malaria vaccine assessed in humans. The accomplishment to manufacture, obtain regulatory approval and to demonstrate an excellent safety profile for this vaccine is unprecedented and holds a promise for PfSPZ vaccines with increased potency.

Autologous tumor cell vaccination combined with systemic CpG-B and IFN-\u03b1 promotes immune activation and induces clinical responses in patients with metastatic renal cell carcinoma: a phase II trial

In this study the toxicity and efficacy of an irradiated autologous tumor cell vaccine (ATV) co-injected with a class-B CpG oligodeoxynucleotide (CpG-B) and GM-CSF, followed by systemic CpG-B and IFN-α administration, were examined in patients with metastatic renal cell carcinoma (mRCC). A single-arm Phase II trial was conducted, in which patients with mRCC were intradermally injected with a minimum of three whole-cell vaccines containing 0.7–1.3 × 107 irradiated autologous tumor cells (ATC), admixed with 1 mg CpG-B and 100 µg GM-CSF, followed by bi-weekly s.c. injections with 8 mg CpG-B and s.c. injections with 6 MU IFN-α three times per week. Fifteen patients were treated according to the protocol. Treatment was well tolerated. Objective clinical responses occurred in three patients, including one long-term complete response. Disease stabilization occurred in another three patients. Positive delayed type hypersensitivity (DTH) responses to ATC were absent before treatment but present in 13 out of 15 patients during treatment. Immune monitoring revealed activation of plasmacytoid dendritic cells, non-classical monocytes and up-regulation of both PD-1 and CTLA4 on effector T cells upon treatment. Moreover, a pre-existing ex vivo IFN-γ response to ATC was associated with clinical response. ATV combined with systemic CpG-B and IFN-α is tolerable, safe, immunogenic and able to elicit anti-tumor responses in patients with mRCC. Immune activation and treatment-induced up-regulation of PD-1 and CTLA4 on circulating T cells further suggest an added benefit of combining this approach with immune checkpoint blockade [added]

IL-15/IL-15Rα/CD80-expressing AML cell vaccines eradicate minimal residual disease in leukemic mice

AbstractEngineered autologous acute myeloid leukemia (AML) cells present multiple leukemia-associated and patient-specific antigens and as such hold promise as immunotherapeutic vaccines. However, prior vaccines have not reliably induced effective antileukemic immunity, in part because AML blasts have immune inhibitory effects and lack expression of the critical costimulatory molecule CD80. To enhance induction of leukemia-specific cytolytic activity, 32Dp210 murine AML cells were engineered to express either CD80 alone, or the immunostimulatory cytokine interleukin-15 (IL-15) with its receptor α (IL-15Rα), or heterodimeric IL-15/IL-15Rα together with CD80 and tested as irradiated cell vaccines. IL-15 is a γc-chain cytokine, with unique properties suited to stimulating antitumor immunity, including stimulation of both natural killer and CD8+ memory T cells. Coexpression of IL-15 and IL-15Rα markedly increases IL-15 stability and secretion. Non-tumor-bearing mice vaccinated with irradiated 32Dp210-IL-15/IL-15Rα/CD80 and challenged with 32Dp210 leukemia had greater survival than did mice treated with 32Dp210-CD80 or 32Dp210-IL-15/IL-15Rα vaccines, whereas no unvaccinated mice inoculated with leukemia survived. In mice with established leukemia, treatment with 32Dp210-IL-15/IL-15Rα/CD80 vaccination stimulated unprecedented antileukemic immunity enabling 80% survival, an effect that was abrogated by anti-CD8 antibody-mediated depletion in vivo. Because, clinically, AML vaccines are administered as postremission therapy, we established a novel model in which mice with high leukemic burdens were treated with cytotoxic therapy to induce remission (<5% marrow blasts). Postremission vaccination with 32Dp210-IL-15/IL-15Rα/CD80 achieved 50% overall survival in these mice, whereas all unvaccinated mice achieving remission subsequently relapsed. These studies demonstrate that combined expression of IL-15/IL-15Rα and CD80 by syngeneic AML vaccines stimulates effective and long-lasting antileukemic immunity.

Modeling the effect of boost timing in murine irradiated sporozoite prime-boost vaccines.

Vaccination with radiation-attenuated sporozoites has been shown to induce CD8+ T cell-mediated protection against pre-erythrocytic stages of malaria. Empirical evidence suggests that successive inoculations often improve the efficacy of this type of vaccines. An initial dose (prime) triggers a specific cellular response, and subsequent inoculations (boost) amplify this response to create a robust CD8+ T cell memory. In this work we propose a model to analyze the effect of T cell dynamics on the performance of prime-boost vaccines. This model suggests that boost doses and timings should be selected according to the T cell response elicited by priming. Specifically, boosting during late stages of clonal contraction would maximize T cell memory production for vaccines using lower doses of irradiated sporozoites. In contrast, single-dose inoculations would be indicated for higher vaccine doses. Experimental data have been obtained that support theoretical predictions of the model.

CCL3 augments tumor rejection and enhances CD8+ T cell infiltration through NK and CD103+ dendritic cell recruitment via IFNγ

ABSTRACTInflammatory chemokines are critical contributors in attracting relevant immune cells to the tumor microenvironment and driving cellular interactions and molecular signaling cascades that dictate the ultimate outcome of host anti-tumor immune response. Therefore, rational application of chemokines in a spatial-temporal dependent manner may constitute an attractive adjuvant in immunotherapeutic approaches against cancer. Existing data suggest that the macrophage inflammatory protein (MIP)-1 family and related proteins, consisting of CCL3 (MIP-1α), CCL4 (MIP-1β), and CCL5 (RANTES), can be major determinant of immune cellular infiltration in certain tumors through their direct recruitment of antigen presenting cells, including dendritic cells (DCs) to the tumor site. In this study, we examined how CCL3 in a murine colon tumor microenvironment, CT26, enhances antitumor immunity. We identified natural killer (NK) cells as a major lymphocyte subtype that is preferentially recruited to the CCL3-rich tumor site. NK cells contribute to the overall IFNγ content, CD103+ DC accumulation, and augment the production of chemokines CXCL9 and CXCL10 for enhanced T cell recruitment. We further demonstrate that both soluble CCL3 and CCL3-secreting irradiated tumor vaccine can effectively halt the progression of established tumors in a spatial-dependent manner. Our finding implies an important contribution of NK in the CCL3 – CD103+ DC – CXCL9/10 signaling axis in determining tumor immune landscape within the tumor microenvironment.

Japanese Kampo medicine ninjin'yoeito synergistically enhances tumor vaccine effects mediated by CD8+ T cells.

Although Japanese traditional herbal medicine (Kampo) has been widely applied to the treatment of various diseases, including cancer, their mechanisms of action have not yet been elucidated in detail, particularly regarding their role in tumor immunology. The present study investigated the antitumor effects of the Japanese Kampo medicine, ninjin'yoeito (NYT; Ren-Shen-Yang-Rong-Tang in Chinese), which was orally administered with or without an irradiated tumor cell vaccine to a subcutaneous CT26 colon carcinoma tumor model. The irradiated tumor cell vaccine in a prophylactic setting significantly delayed tumor growth in mice fed a control diet, whereas a diet containing NYT alone did not exert any antitumor effects in vivo. However, the inhibition of tumor growth was significantly greater in vaccinated mice fed the NYT diet compared with in vaccinated mice given the control diet. These results suggest that NYT synergistically enhances the effects of the antitumor vaccine. The depletion of cluster of differentiation (CD)8+ T cells abrogated these effects, indicating that antitumor activity required CD8+ T cells. Furthermore, reductions in CD4+ CD25+ and forkhead box protein 3+ T regulatory cell numbers were more apparent between vaccinated mice fed the NYT diet and non-vaccinated mice fed the control diet than between vaccinated mice and non-vaccinated mice fed the control diet, suggesting that the weaker impact of T regulatory cells contributes to the augmentation of antitumor immunity by CD8+ T cells in vaccinated mice fed with NYT. Overall, these results indicate that NYT synergistically enhances the effects of the prophylactic tumor vaccine mediated by CD8+ T cells and that this Japanese Kampo medicine has potential as a useful adjuvant agent for cancer immunotherapy.

Therapeutic Efficacy of 4-1BB Costimulation Is Abrogated by PD-1 Blockade in a Model of Spontaneous B-cell Lymphoma.

Combinations of mAbs that target various components of T-cell activation/inhibition may work synergistically to improve antitumor immunity against cancer. In this study, we investigated the therapeutic potential of combining an anticancer vaccination strategy with antibodies targeting an immune stimulatory (4-1BB) and immune inhibitory (PD-1) receptor, in a preclinical model of spontaneously arising c-Myc-driven B-cell lymphoma. In Eμ-myc transgenic mice, we reveal that 4-1BB agonistic mAb treatment alone was sufficient to drive antitumor immunity and prevent disease progression in 70% of mice. When combined with an α-GalCer-loaded, irradiated tumor cell vaccine, 4-1BB mAb treatment led to increased expansion of effector CD8 T-cell populations and protection of long-term surviving mice against tumor rechallenge. Unexpectedly, PD-1 blockade did not provide therapeutic benefit. The T-cell-promoting effects and antitumor activity of 4-1BB mAb were diminished when used simultaneously with a PD-1-blocking mAb. This was associated with a rapid and dramatic reduction in effector CD8+ T-cell subsets in the presence of PD-1 blockade. These findings reveal that supporting T-cell activation therapeutically is effective for controlling B-cell lymphomas; however, caution is required when combining antibody-mediated modulation of both costimulatory and coinhibitory T-cell receptors. Cancer Immunol Res; 5(3); 191-7. ©2017 AACR.

Irradiated VEGF164-modified tumor cell vaccine protected mice from the parental tumor challenge.

Vascular endothelial growth factor (VEGF) is an important regulating molecule of angiogenesis in tumor formation and progression. Cancer cells always secrete VEGF to stimulate angiogenesis that facilitate growth and invasion of the tumor. In this study, we established a VEGF164 overexpressing LL/2 lung cancer cell model and found that the postirradiated VEGF164-modified tumor cells protected the host against the challenge with LL/2 wild-type tumor cells. Histochemical assay showed that there were large areas of tumor necrosis with macrophage infiltration in the mice vaccinated with the VEGF164-modified tumor vaccine. T-cells isolated from the vaccinated mice showed cytotoxicity against the parental tumor cells in a dose-dependent manner. Meanwhile, sera from the mice vaccinated with LL/2-VEGF164 showed higher titers of antibodies against parental tumor cells compared with the nonvaccinated groups. Our results indicated that VEGF164-modified tumor vaccine could modulate host antitumor immune response and hold therapeutic potential for cancer.

X-ray Irradiated Vaccine Confers protection against Pneumonia caused by Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a gram-negative bacterium and one of the leading causes of nosocomial infection worldwide, however, no effective vaccine is currently available in the market. Here, we demonstrate that inactivation of the bacteria by X-ray irradiation inhibits its replication capability but retained antigenic expression functionally thus allowing its use as a potential vaccine. Mice immunized by this vaccine were challenged by the parental strain, the O-antigen-homologous strain PAO-1 (O2/O5) and heterologous strain PAO-6 (O6) in an acute pneumonia model. We further measured the protective effect of the vaccine, as well as host innate and cellular immunity responses. We found immunized mice could protect against both strains. Notably, the antiserum only had significant protective role against similar bacteria, while adoptive transfer of lymphocytes significantly controlled the spread of the virulent heterologous serogroup PAO-6 infection, and the protective role could be reversed by CD4 rather than CD8 antibody. We further revealed that vaccinated mice could rapidly recruit neutrophils to the airways early after intranasal challenge by PAO-6, and the irradiated vaccine was proved to be protective by the generated CD4+ IL-17+ Th17 cells. In conclusion, the generation of inactivated but metabolically active microbes is a promising strategy for safely vaccinating against Pseudomonas aeruginosa.

Effects of tumor vaccine expressing Granulocyte–Macrophage Colony Stimulating Factor and interleukin-18 fusion on cancer cells and its possible application for cancer immunotherapy

To access antitumor effects of a combined Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF) and interleukin-18 (IL-18), cDNA fusion of murine GM-CSF and mature IL-18 (GMIL-18) was constructed and transfected in mammalian cells. GMIL-18 fusion protein was highly secreted and displayed bifunctional activities, possessing immune response initiation and cytokine roles, including IFN-γ induction in mouse splenocytes and increased proliferation of GM-CSF-dependent cells, M-NSF-60. The GMIL-18 secreting tumor vaccine was generated and it strongly stimulated differentiation of dendrite cells (DCs) and effusive CD8+ and CD4+ cell infiltration into tumor mice. Moreover, growth of CT26 mouse colon cancer cells was significantly retarded by GMIL-18 (CT26GMIL-18), but not by CT26GM-CSF- or CT26IL-18. The efficiency of prophylactic vaccination was greater than that of therapeutic vaccination in terms of tumor size and its inhibitory role in proliferation. In micrometastasis analysis of tumor models, γ-ray irradiated GMIL-18 tumor vaccine showed a smaller number of liver-meta tumor nodules in mouse liver cells. We concluded that bifunctional GMIL-18 fusion protein could be applied as an immune therapy for cancer treatments.

A therapeutic cancer vaccine against GL261 murine glioma.

BackgroundGlioblastoma (GBM) is the deadliest of brain tumors. Standard treatment for GBM is surgery, followed by combined radiation therapy and chemotherapy. Current therapy prolongs survival but does not offer a cure. We report on a novel immunotherapy against GBM, tested in an animal model of C57BL/6 mice injected intra-cranially with a lethal dose of murine GL261 glioma cells.MethodsTen week-old C57BL/6 mice were anesthetized before injection of 2 × 104 GL261 cells in the right cerebral hemisphere and after 3 days half of the mice were administered a single subcutaneous (s.c.) injection of irradiated semi-allogeneic vaccine, while mock-vaccinated mice received a s.c. injection of phosphate-buffered saline (PBS). Tumor engraftment was monitored through bioluminescence imaging (BLI). Length of animal survival was measured by Kaplan–Meier graphs and statistics. At time of sacrifice brain tissue was processed for estimation of tumor size and immunohistochemical studies.ResultsOverall survival of vaccinated mice was significantly longer compared to mock-vaccinated mice. Five to ten percent of vaccinated mice survived more than 90 days following the engraftment of GL261 cells in the brain and appeared to be free of disease by BLI. Tumor volume in the brain of vaccinated mice was on average five to ten-fold smaller compared to mock-vaccinated mice. In vaccinated mice, conspicuous microglia infiltrates were observed in tumor tissue sections and activated microglia appeared to form a fence along the perimeter of the tumor cells. The results of these animal studies persuaded the Office of Orphan Products Development of the Food and Drug Administration (FDA) to grant Orphan Drug Designation for treatment of GBM with irradiated, semi-allogeneic vaccines.ConclusionsOur preclinical observations suggest that semi-allogeneic vaccines could be tested clinically on subjects with GBM, as an adjuvant to standard treatment.

Effect of HSV-IL12 Loaded Tumor Cell-Based Vaccination in a Mouse Model of High-Grade Neuroblastoma.

We designed multimodal tumor vaccine that consists of irradiated tumor cells infected with the oncolytic IL-12-expressing HSV-1 virus, M002. This vaccine was tested against the syngeneic neuroblastoma mouse model Neuro 2a injected into the right caudate nucleus of the immunocompetent A/J mice. Mice were vaccinated via intramuscular injection of multimodal vaccine or uninfected irradiated tumor cells at seven and 14 days after tumor establishment. While there was no survival difference between groups vaccinated with cell-based vaccine applied following tumor injection, a premunition prime/boost vaccination strategy produced a significant survival advantage in both groups and sustained immune response to an intracranial rechallenge of the same tumor. The syngeneic but unrelated H6 hepatocellular tumor cell line grew unrestricted in vaccinated mice, indicative of vaccine-mediated specific immunity to Neuro 2a tumors. Longitudinal analyses of tumor-infiltrating lymphocytes revealed a primary adaptive T cell response involving both CD4+ and CD8+ T cell subsets. Spleen cell mononuclear preparations from vaccinated mice were significantly more cytotoxic to Neuro 2a tumor cells than spleen cells from control mice as demonstrated in a four-hour in vitro cytotoxicity assay. These results strongly suggest that an irradiated whole cell tumor vaccine incorporating IL-12-expressing M002 HSV can produce a durable, specific immunization in a murine model of intracranial tumor.

Colony stimulating factors secreted by irradiated autologous tumor cell vaccines inhibit immunity

Meeting abstracts Autologous tumor cell-based vaccines (ATCVs) have a number of potential advantages including multivalency and patient specificity. ATCVs contain many potential antigens, both known and unknown which potentiate polyclonal responses capable of responding to a more diverse population