Injection Of Dendritic Cells Research Articles

Modulated Electro-Hyperthermia-Induced Tumor Damage Mechanisms Revealed in Cancer Models.

The benefits of high-fever range hyperthermia have been utilized in medicine from the Ancient Greek culture to the present day. Amplitude-modulated electro-hyperthermia, induced by a 13.56 MHz radiofrequency current (mEHT, or Oncothermia), has been an emerging means of delivering loco-regional clinical hyperthermia as a complementary of radiation-, chemo-, and molecular targeted oncotherapy. This unique treatment exploits the metabolic shift in cancer, resulting in elevated oxidative glycolysis (Warburg effect), ion concentration, and electric conductivity. These promote the enrichment of electric fields and induce heat (controlled at 42 °C), as well as ion fluxes and disequilibrium through tumor cell membrane channels. By now, accumulating preclinical studies using in vitro and in vivo models of different cancer types have revealed details of the mechanism and molecular background of the oncoreductive effects of mEHT monotherapy. These include the induction of DNA double-strand breaks, irreversible heath and cell stress, and programmed cells death; the upregulation of molecular chaperones and damage (DAMP) signaling, which may contribute to a secondary immunogenic tumor cell death. In combination therapies, mEHT proved to be a good chemosensitizer through increasing drug uptake and tumor reductive effects, as well as a good radiosensitizer by downregulating hypoxia-related target genes. Recently, immune stimulation or intratumoral antigen-presenting dendritic cell injection have been able to extend the impact of local mEHT into a systemic “abscopal” effect. The complex network of pathways emerging from the published mEHT experiments has not been overviewed and arranged yet into a framework to reveal links between the pieces of the “puzzle”. In this paper, we review the mEHT-related damage mechanisms published in tumor models, which may allow some geno-/phenotype treatment efficiency correlations to be exploited both in further research and for more rational clinical treatment planning when mEHT is involved in combination therapies.

Optimal control of variable-order fractional model for delay cancer treatments

This article presents a fractional-order mathematical model of the biological phenomena that occur in cancer therapy. The formulation generalizes the one proposed by Soto-Ortiza and Finley that consists of eighteen integer order differential equations and intends to serve as a platform for cancer treatment design. The fractional model is used to test the hypothesis that a combination of anti-Vascular Endothelial Growth Factor (VEGF) treatment with immunotherapy, involving injections of unlicensed dendritic cells (DC), can lead to the tumor eradication by concealing the suppressor VEGF. The new approach adopts derivatives defined in the Caputo sense and implements an optimal control strategy. Two control variables, one for immunotherapy and another for anti-angiogenic therapy, are considered for reducing the number of the cancer cells. Moreover, two numerical methods are introduced and their stability analysis is studied. Numerical simulations illustrate the proposed concepts.

A prospective phase I trial of dendritic cell-based cryoimmunotherapy in metastatic castration-resistant prostate cancer.

3029 Background: Dendritic cell (DC)-based cryoimmunotherapy (CryoIT) was used to treat metastatic castration-resistant prostate cancer in a Phase I clinical trial. Primary objective was safety of treatment. Secondarily, clinical, radiological and immunological treatment responses were investigated. Methods: In 18 patients cryoablation by a freeze-thaw process under general anesthesia was performed, followed by intratumoral autologous immature DC injection. In the last 9 patients checkpoint inhibition of either CTLA-4 or PD-1 was added. Subjects had minimum 46 weeks follow-up. Adverse events (AEs) and blood analyses were registered at all visits. Disease progression was determined by three imaging modalities according to (i)RECISTv1.1 and progression-free survival (PFS) by Kaplan-Meier method. Circulating tumor cells (CTC/7.5 mL, CellSearch) and ultradeep T-cell receptor (TCR) b-chain sequences (TCRSafe) were enumerated. Patients were separated by CTC into none (n=10), 1-4 (n=4) and ≥ 5 (n=4). Health related quality of life (HRQoL) measured by EORTC-QLQ C30 questionnaire were answered at inclusion, and 10, 22 and 46 weeks post CryoIT. Scores were calculated according to the EORTC manual. Results: Subjects progressing within 22 weeks had higher PSA (p=0.03). AE profile of the total cohort (n=18) was comparable with interim reports (n=13); of 20 possible DC-related AEs one was severe (urinary retention) and 19 mild-to-moderate, and spread independent of treatment regime. Maximum tolerated dose of DC was not reached. By 46 weeks, imaging showed 6 patients partial response or stable disease. Median PFS was 150 days in total cohort. Pretreatment CTC counts ≥5 indicated higher progression rates and recurring CTC. Ultradeep TCR-sequencing showed more prevalent and higher expressed (>5-fold) new TCR clonotypes at 2-6 weeks in men without progression. Participants reported high and stable HRQoL scores throughout the study. However, presence of CTC was associated with worse HRQoL scores at week 10 (p=0.031) and 22 (p=0.005). Conclusions: DC treatment seems safe and well tolerated, also combined with checkpoint inhibitors. Effect is indicated in subjects with moderate pre-treatment PSA levels. Immune responses are suggested by higher number of novel TCR clonotypes in men with non-progressive disease. Clinical trial information: NCT02423928 .

Safety and Long-Term Outcome of Intratumoral Injection of OK432-Stimulated Dendritic Cells for Hepatocellular Carcinomas After Radiofrequency Ablation

Dendritic cell (DC)–based immunotherapies are believed to help eradicate residual tumor cells, including hepatocellular carcinoma (HCC). Here, we assessed the safety and clinical response to OK432-stimulated monocyte-derived DCs (MoDCs) in treating HCC after radiofrequency ablation (RFA). MoDCs were derived from 30 HCC patients in the presence of interleukin-4 and granulocyte-macrophage colony stimulating factor for 5 days and then cultured for 2 more days in the medium (basic protocol) or stimulated with OK432. On day 7, DCs were harvested and percutaneously injected into HCC tumors after RFA. We observed no grade 3 or 4 National Cancer Institute Common Toxicity Criteria adverse events. Kaplan-Meier analysis indicated that patients treated with RFA + OK432-stimulated DCs transfer had longer recurrence-free survival than those treated with RFA + basic-protocol DCs (median: 24.8 vs 13.0 months; P = .003). RFA with DC infusion can enhance various tumor-associated antigen (TAA)–specific T-cell responses. Additionally, the 5-year RFS rate for patients with significantly increased TAA-specific T-cell responses was much higher than for other patients (50.0% vs. 7.7%; P = .030). Our study provides useful information for development of HCC immunotherapies (trial registration: UMIN000001701).

Advances and perspectives of dendritic cell-based active immunotherapies in follicular lymphoma.

Follicular lymphoma (FL) is a remarkably immune-responsive malignancy, which is still considered incurable. As, standard immunochemotherapy is complex, toxic and not curative, improvement in FL care is now a crucial topic in hemato-oncology. Recently, we and others have shown that dendritic cell (DC)-based therapies allow a specific immune response associated with sustained lymphoma regression in a proportion of low-tumor burden FL patients. Importantly, the rate of objective clinical response (33-50%) and of sustained remission is remarkably higher compared to similar studies in solid tumors, corroborating the assumption of the immune responsiveness of FL. Our experimental intra-tumoral strategy combined injection with rituximab and interferon-α-derived dendritic cells (IFN-DC), a novel DC population particularly efficient in biasing T-helper response toward the Th1 type and in the cross-priming of CD8 + T cells. Noteworthy, intra-tumoral injection of DC is a new therapeutic option based on the assumption that following the induction of cancer-cell immunogenic death, unloaded DC would phagocytize in vivo the tumor associated antigens and give rise to a specific immune response. This approach allows the design of easy and inexpensive schedules. On the other hand, advanced and straightforward methods to produce clinical-grade antigenic formulations are currently under development. Both unloaded DC strategies and DC-vaccines are suited for combination with radiotherapy, immune checkpoint inhibitors, immunomodulators and metronomic chemotherapy. In fact, studies in animal models have already shown impressive results, while early-phase combination trials are ongoing. Here, we summarize the recent advances and the future perspectives of DC-based therapies in the treatment of FL patients.

Autologous and Pooled Tumor Lysates in Combined Immunotherapy of Patients with Glioblastoma

Although major progress has been made in the standard treatment for glioblastomas, encompassing the maximal surgical resection, chemotherapy and radiation therapy, it is possible to increase survival rates significantly only in a few patients. Therefore, it is necessary to explore new therapeutic modalities, one of which is immunotherapy.The aim of the study was to evaluate the efficacy of the combined use of autologous and pooled tumor lysates in comprehensive treatment of patients with glioblastoma.Materials and MethodsAll patients (n=58, including 30 males and 28 females aged 18–70 years) were randomized into three groups, two of which received immunotherapy based on injection of autologous dendritic cells pulsed with autologous tumor lysates (first protocol) or pooled lysates (second protocol) from more than one tumor, in addition to the planned standard treatment. The patients of group 3 (control) received the standard comprehensive treatment encompassing the maximum safe tumor resection followed by radiation therapy and chemotherapy.ResultsThe tolerability of both applied immunotherapy protocols was good: there were no anaphylactic reactions observed or patients who prematurely discontinued participation in the study. The final analysis of the data revealed no significant differences in median survival values of patients in each of the three groups. However, when analyzing the Karnofsky Performance Status in patients of group 2, it was found that it tended to improve.ConclusionThe study shows that the proposed immunotherapy protocols are safe for clinical use and have the potential to improve the patient’s life quality. However, these findings should be considered intermediate until the findings of multicenter randomized clinical trials with a larger number of patients are obtained.

Abstract PR13: Adjuvant TLR-3 administration enhances proinflammatory immune responses and is associated with extended survival in glioblastoma patients treated with dendritic cell vaccination

Abstract Malignant glioma, associated with a poor prognosis, is the most common primary malignant brain tumor in adults. We and others have documented immune responses following dendritic cell (DC) vaccination as an active immunotherapeutic treatment for these patients. In this phase II clinical trial, we randomized malignant glioma patients to receive autologous tumor lysate pulsed DC vaccination with and without adjuvant Toll-like receptor (TLR) agonists. TLRs are present on dendritic cells and serve to modulate immune responses. Twenty-three patients with WHO grade III or IV glioma were treated with three intradermal injections of autologous tumor lysate-pulsed DC on days 0, 14, and 28 followed by an adjuvant placebo, TLR-7 agonist (resiquimod), or TLR-3 agonist (Poly ICLC). Mass cytometry (CyTOF) was used to analyze immune cell populations of patient peripheral blood mononuclear cells (PBMC) before and following treatment. DC-vaccinated patients who received adjuvant Poly ICLC treatment had a significantly improved median survival of 54 months over placebo (11 months) and adjuvant resiquimod (17 months) groups (P<0.01). CyTOF and single-cell RNA sequencing (scRNseq) gene expression analysis of systemic PBMCs from patients demonstrated increased immune cell activation and expression of proinflammatory genes. Notably, the expansion of a heterogenous myeloid cell population was noted to correlate with increased survival, corroborating preclinical evidence that these cells modulate adaptive immunity in the tumor microenvironment. Overall, these findings suggest that adjuvant Poly ICLC treatment improves outcomes with autologous lysate-pulsed DC vaccine treatment via modulation of proinflammatory pathways. This abstract is also being presented as Poster B27. Citation Format: Joseph P. Antonios, Richard G. Everson, Aaron Mochizuki, Sara Khattab, Horacio Soto, Prashant Romiyo, Matthew Z. Sun, Diana Moughon, Emma Billingslea-Yoon, Sylvia Odesa, Gang Li, Eric Kawaguchi, Alex Salazar, William Yong, Jason Schlossman, Benjamin Ellingson, Anthony C. Wang, Timothy Cloughesy, Robert M. Prins, Linda M. Liau. Adjuvant TLR-3 administration enhances proinflammatory immune responses and is associated with extended survival in glioblastoma patients treated with dendritic cell vaccination [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr PR13.

Effects of Dendritic Cell Vaccine Activated with Components of Lieshmania Major on Tumor Specific Response.

Dendritic cells (DCs) contribute essentially to the outset and course of immune responses. So in patients with malignancy, there have been considerable interests in use of these cells in different interventions. To evaluate the impact of Leishmania major's components on DC maturation and their use as a therapeutic agent against tumor cells. The cancer model was induced by injection of WEHI-164 cells (BALB/c derived fibrosarcoma cell line) subcutaneously in the right flank of animals. Bone-marrow derived DCs (BMDCs) were cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4. After 5 days, tumor lysate, Leishmania major's lysate, and Lipopolysaccharide (LPS) were added to the culture and incubated for 2 days. IL-12 production in DCs was measured by ELISA. For Immunotherapy, Mice received DCs subcutaneously around the tumor site. Two weeks after DCs injection, cytotoxicity assay and infiltration of CD8+ lymphocytes were evaluated. Our results showed that immunotherapy with dendritic cells exposed to Leishmania extract led to producing a higher amount of IL-12, compare to the control group. A considerable increment in specific cytotoxic T cells activity, diminished tumor growth rate and improved survival of immunized animals were seen. This study indicates that the use of Leishmania major extract, as well as LPS, can enhance the efficiency of DC-based vaccines and provides a basis for the use of Leishmania major in DC-targeted clinical therapies.

Manipulation of the tumor microenvironment by cytokine gene transfection enhances dendritic cell-based immunotherapy.

The tumor microenvironment strongly influences clinical outcomes of immunotherapy. By transfecting genes of relevant cytokines into tumor cells, we sought to manipulate the microenvironment so as to elicit activation of T helper type 1 (Th1) responses and the maturation of dendritic cells (DCs). Using a synthetic vehicle, the efficiency of in vivo transfection of GFP‐cDNA into tumor cells was about 7.5% by intratumoral injection and about 11.5% by intravenous injection. Survival was significantly improved by both intratumoral and intravenous injection of the plasmid containing cDNA of interferon‐gamma, followed by intratumoral injection of DCs presenting the tumor antigens. Also, tumor growth was inhibited by these treatments. A more significant effect on survival and tumor growth inhibition was observed following injection of the plasmid containing cDNA of CD40 ligand, which is a potent inducer of DC‐maturation. Furthermore, the co‐injection of both IFNγ‐ and CD40 ligand‐encoding cDNA‐plasmids, followed by DC treatment, gave rise to further marked and enhancement, including 100% survival and more than 50% complete remission. This treatment regimen elicited significant increases in mature DCs and types of cells contributing to Th1 responses, and significant decreases in immune suppressor cells in the tumor. In the spleen, the treatment significantly increased activities of tumor‐specific killer and natural killer cells, but no alteration was observed in mature DCs or suppressor cells. These results indicate that transfection of these cytokine genes into tumor cells significantly alter the tumor microenvironment and improve the therapeutic results of DC‐based immunotherapy.

Low Photosensitizer Dose and Early Radiotherapy Enhance Antitumor Immune Response of Photodynamic Therapy-Based Dendritic Cell Vaccination.

Recent studies have highlighted the potential of photodynamic therapy (PDT) to induce immunogenic cell death (ICD). The clinical use of photosensitizers (PS) to stimulate an anticancer immune response, and not to sterilize tumor cells, may however require some optimizations. Here, we examined how the dose of PS and the scheduling of PDT influence the generation of danger-associated molecular patterns proteins (DAMPs) and favor T cell antitumor activity. We found that upon photoactivation, a low dose of the non-porphyrinic PS OR141 was more prone than higher doses to induce DAMPs in vitro and to inhibit squamous cell carcinoma growth in mice. We further used PDT-killed cancer cells to prime dendritic cells (DC) and stimulate their maturation to evaluate whether the timing of their injection could influence the antitumor effects of radiotherapy. While PDT-based DC vaccination administered before radiotherapy failed to increase tumor growth inhibition, DC injection in the peri-radiotherapy period led to significant tumor growth delay, emphasizing the importance of the coincidence of T cell activation and alterations of the tumor bed. In conclusion, the use of OR141 as a bona fide ICD inducer led us to unravel both the non-linear relationship between PS concentration and PDT-induced antitumor immune response, and the value of an optimal timing of PDT when co-administered with conventional anticancer therapies. This study therefore stresses the necessity of adapting the clinical use of PDT when the goal is to promote an immune response and identifies PDT-based DC vaccination as a suitable modality to reach such objective.

Abstract LB-076: Personal neoantigen immunotherapy in hepatocellular carcinoma

Abstract Hepatocellular carcinoma (HCC) is one of the most common cancers and the leading causes of mortality in China with limited therapeutic options. To investigate whether neoantigens could induce tumor specific immune responses in patients with HCC, neoantigen stimulating cellular therapy (neo-MASCT) was applied after radical resection. Neo-MASCT was a cell-based immunotherapy with injections of mature dendritic cells (DCs) loaded with a peptide pool of multiple shared tumor associated antigens (TAAs) and several personalized neoantigens followed by autologous T cells stimulated by these DCs. To obtain neoantigens, fresh tumor samples were acquired immediately after biopsy or surgery for subsequently WES and RNAseq. All mutations including SNV, non-frame shift insert/deletion (Indel), and neoORF were detected by comparing NGS data from tumors to normal tissues. All neo-epitope candidates were predicted by our own proprietary algorithm MASNEO according to the patient’s HLA class I genotypes. Long neoantigen peptides containing 25-31 amino acids with higher affinities were selected for further synthesis and treatment. Peptides containing multiple neo-epitopes were preferred. Until now, eight patients had received neo-MASCT, and seven of them were tested for specific immune responses against both TAAs and neoantigens using IFNγ Elispot assay. The results showed that Neo-MASCT induced TAA-specific immune responses in five patients (5/7, 71%), and induced neoantigen-specific immune responses in six patients (6/7, 86%), respectively. One patient demonstrated specific T cell responses against all the five neoantigen peptides (5/5, 100%) after neo-MASCT treatment. The average responsive rate of neoantigens was 65% (22/34 peptides) in the six responding patients. In conclusion, our results demonstrate that neo-MASCT is well-tolerated in HCC patients and elicits immune responses against multiple tumor antigens, especially personalized neoantigens. We will continuously monitor the immune responses against neoantigens, and use the results to train and optimize our predicting algorithm. We will also evaluate the clinical benefit of neo-MASCT in further clinical trials with more patients. Citation Format: Sui Peng, Zhenwei Peng, Lixia Xu, Jie Mei, Longqing Tang, Yanyan Han, Ming Kuang. Personal neoantigen immunotherapy in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-076.

Intratumoral injection of dendritic cells overexpressing interleukin‑12 inhibits melanoma growth.

The present study aimed to investigate the antitumor effects of an intratumoral injection of dendritic cells (DCs) overexpressing interleukin-12 (IL‑12) on melanoma. DCs, isolated from mouse spleen, were gene‑modified using an IL‑12 overexpression vector. Melanoma B6 cells were injected into C57BL/6 mice to generate tumors. Thereafter, DCs overexpressing IL‑12 were injected into the tumors, and tumor volume was subsequently measured. Pathological changes in tumor tissue were detected by hematoxylin and eosin staining. The expression of interleukin-4 (IL‑4) and IL‑12 in tumors was measured by enzyme‑linked immunosorbent assay, real‑time PCR and western blotting. DCs were successfully isolated and a lentivirus vector expressing IL‑12 was constructed. After intratumoral injection of phosphate‑buffered saline (control group), tumor cells exhibited malignant growth; whereas tumors injected with DCs (DC group) or DCs + empty vector (DC + vector group) exhibited a small amount of inflammatory cell infiltration and limited areas of tissue necrosis. In contrast, tumors injected with DCs overexpressing IL‑12 (DC + IL‑12 group) displayed severe tissue necrosis, loss of cell structure, and inflammatory cell infiltration. Compared with the control group, the tumor volumes were significantly lower in the DC, the DC + vector and the DC + IL‑12 groups, while the expression of IL‑12 and IL‑4 in the tumors was significantly higher. Importantly, the most marked changes in tumor volume and IL‑12 and IL‑4 expression were in the DC + IL‑12 group, which were significantly greater than those in tumors treated with unmodified DCs. Hence, intratumoral injection of DCs overexpressing IL‑12 exerted strong antitumor effects in melanoma, and biotherapy with DCs overexpressing IL‑12 is a potential treatment strategy for melanoma.

Expansion of effector and memory T cells is associated with increased survival in recurrent glioblastomas treated with dendritic cell immunotherapy

BackgroundThe efficacy of dendritic cell (DC) immunotherapy as a single therapeutic modality for the treatment of glioblastoma (GBM) patients remains limited. In this study, we evaluated in patients with GBM recurrence the immune-mediated effects of DC loaded with autologous tumor lysate combined with temozolomide (TMZ) or tetanus toxoid (TT).MethodsIn the phase I-II clinical study DENDR2, 12 patients were treated with 5 DC vaccinations combined with dose-dense TMZ. Subsequently, in eight patients, here defined as Variant (V)-DENDR2, the vaccine site was preconditioned with TT 24 hours before DC vaccination and TMZ was avoided. As a survival endpoint for these studies, we considered overall survival 9 months (OS9) after second surgery. Patients were analyzed for the generation of effector, memory, and T helper immune response.ResultsFour of 12 DENDR2 patients reached OS9, but all failed to show an immunological response. Five of eight V-DENDR2 patients (62%) reached OS9, and one patient is still alive (OS >30 months). A robust CD8+ T-cell activation and memory T-cell formation were observed in V-DENDR2 OS>9. Only in these patients, the vaccine-specific CD4+ T-cell activation (CD38+/HLA-DR+) was paralleled by an increase in TT-induced CD4+/CD38low/CD127high memory T cells. Only V-DENDR2 patients showed the formation of a nodule at the DC injection site infiltrated by CCL3-expressing CD4+ T cells.ConclusionsTT preconditioning of the vaccine site and lack of TMZ could contribute to the efficacy of DC immunotherapy by inducing an effector response, memory, and helper T-cell generation.

A Characterization of Dendritic Cells and Their Role in Immunotherapy in Glioblastoma: From Preclinical Studies to Clinical Trials

Glioblastoma (GBM) is the most common and fatal primary central nervous system malignancy in adults with a median survival of less than 15 months. Surgery, radiation, and chemotherapy are the standard of care and provide modest benefits in survival, but tumor recurrence is inevitable. The poor prognosis of GBM has made the development of novel therapies targeting GBM of paramount importance. Immunotherapy via dendritic cells (DCs) has garnered attention and research as a potential strategy to boost anti-tumor immunity in recent years. As the “professional” antigen processing and presenting cells, DCs play a key role in the initiation of anti-tumor immune responses. Pre-clinical studies in GBM have shown long-term tumor survival and immunological memory in murine models with stimulation of DC activity with various antigens and costimulatory molecules. Phase I and II clinical trials of DC vaccines in GBM have demonstrated some efficacy in improving the median overall survival with minimal to no toxicity with promising initial results from the first Phase III trial. However, there remains no standardization of vaccines in terms of which antigens are used to pulse DCs ex vivo, sites of DC injection, and optimal adjuvant therapies. Future work with DC vaccines aims to elucidate the efficacy of DC-based therapy alone or in combination with other immunotherapy adjuvants in additional Phase III trials.

GM-CSF Culture Revisited: Preparation of Bulk Populations of Highly Pure Dendritic Cells from Mouse Bone Marrow.

Dendritic cells (DC) loaded with specific peptides are strongly immunogenic for T cells and can be used for cancer immunotherapy. For immunogenic tumors such as melanoma, injection of autologous DC loaded with tumor cell extracts or peptides can induce tumor regression but in only a small proportion of patients. Nevertheless, recent studies on the efficacy of checkpoint blockade for boosting antitumor immunity plus advances in defining tumor neoantigens are stimulating renewed interest in DC immunotherapy. Despite intensive investigation, however, preparation of bulk populations of mature DC has proved difficult, and most preparations contain a significant proportion of potentially tolerogenic immature DC. In this study, we have modified the well-established GM-CSF culture system to prepare substantial quantities of highly pure (>95%) mature DC from mouse bone marrow cells and defined their progenitors. We show that obtaining high yields and purity of DC are heavily dependent on cell density in the cultures and the tempo of addition of growth and maturation stimuli. When loaded with specific peptide, the DC are strongly immunogenic for CD4 and CD8 T cells in vivo and elicit effective antitumor immunity.

Conjugated Polymer Brush Based on Poly(l-lysine) with Efficient Ovalbumin Delivery for Dendritic Cell Vaccine

Dendritic cell (DC)-based vaccines consist of antigens and antigen-presenting cells, such as DCs, that can induce antitumor immune response and extend the lives of patients. In this research, a water-soluble conjugated polymer brush (WSCPB) made of poly(l-lysine) (PLL) and poly(p-phenyleneethynylene) (PPE) was applied to an antigen delivery system for the development of a DC vaccine. We synthesized the WSCPB with a lower proportion of the rigid PPE polymer backbone and a large amount of PLL side chains. The rigid backbone retained a stable optical performance within the experimental range, which enabled the visualization of the payload and cellular imaging as a reporter. Because of the unique brushlike structure, PPE-PLL exhibited not only excellent water solubility but also outstanding antigen-loading capacity. Ovalbumin (OVA), a model antigen in different research, could be adsorbed onto PPE-PLL and then taken up by DCs. Subsequently, DC maturation and cytokine release would be induced by the antigen. In vivo, strong immune responses were induced after the injection of antigen-pulsed DCs, and the level of cytokines in the serum was significantly increased. In addition, the study of the in vivo tumor-suppressor activity of these antigen-pulsed DCs revealed that the DC vaccine induced strong immune responses and thereby effectively inhibited tumor development.

Developing a Minimally Structured Mathematical Model of Cancer Treatment with Oncolytic Viruses and Dendritic Cell Injections.

Mathematical models of biological systems must strike a balance between being sufficiently complex to capture important biological features, while being simple enough that they remain tractable through analysis or simulation. In this work, we rigorously explore how to balance these competing interests when modeling murine melanoma treatment with oncolytic viruses and dendritic cell injections. Previously, we developed a system of six ordinary differential equations containing fourteen parameters that well describes experimental data on the efficacy of these treatments. Here, we explore whether this previously developed model is the minimal model needed to accurately describe the data. Using a variety of techniques, including sensitivity analyses and a parameter sloppiness analysis, we find that our model can be reduced by one variable and three parameters and still give excellent fits to the data. We also argue that our model is not too simple to capture the dynamics of the data, and that the original and minimal models make similar predictions about the efficacy and robustness of protocols not considered in experiments. Reducing the model to its minimal form allows us to increase the tractability of the system in the face of parametric uncertainty.

Summary of the Third International Workshop on Clinical Tolerance.

The Third International Workshop on Clinical Tolerance was held in Stanford, California, September 8-9, 2017. This is a summary of Workshop presentations of clinical trials designed to withdraw or minimize immunosuppressive (IS) drugs in kidney and liver transplant patients without subsequent evidence of rejection. All clinical protocols had in common the use of donor or recipient cell therapy combined with organ transplantation. Tolerance to HLA matched and mismatched living donor kidney transplants with complete withdrawal of IS drugs without subsequent rejection for up to 14 years of observation was achieved in more than 50 patients enrolled in trials in four medical centers after the establishment of transient or persistent chimerism. Complete IS drug withdrawal without chimerism was reported in a prospective trial of liver transplantation combined with injection of regulatory T cells. IS drug minimization without rejection was reported in recipients of living donor kidney transplants enrolled in the One Study consortium after injection of recipient regulatory T cells, or injection of donor regulatory monocytes or dendritic cells. In conclusion, considerable progress has been made in achieving IS drug withdrawal after cell therapy in recipients of organ transplants.

Rsad2 is necessary for mouse dendritic cell maturation via the IRF7-mediated signaling pathway

Dendritic cells (DCs) are the most potent professional antigen presenting cells and inducers of T cell-mediated immunity. However, few specific markers of mature DCs (mDC) have been reported. A previous microarray analysis revealed expression of mDC-specific genes and identified Rsad2 (radical S-adenosyl methionine domain containing 2) as a candidate specific marker for DC maturation. Mouse bone marrow-derived DCs were transfected with Rsad2 siRNA and examined by flow cytometry, ELISA, western, and confocal microscopy. C57BL/6 mice received intravenously B16F10 cells to establish a pulmonary metastasis model. Tumor-bearing mice then received subcutaneously two injections of mDCs or Rsad2 knockdown DCs. The cytotoxic T lymphocyte (CTL) population was examined from splenocytes of DC-vaccinated mice by flow cytometry. Rsad2 was induced at high levels in LPS-stimulated mDCs and mDC function was markedly attenuated under conditions of Rsad2 knockdown. Moreover, Rsad2 was necessary for mDC maturation via the IRF7-mediated signaling pathway. The importance of Rsad2 was confirmed in an Rsad2 knockdown lung metastasis mouse model in which mDCs lost their antitumor efficacy. Data on the CTL population further supported the results as above. Taken together, Rsad2 was an obvious and specific marker necessary for DC maturation and these findings will be clearly helpful for further understanding of DC biology.

Induction of Tertiary Lymphoid Structures With Antitumor Function by a Lymph Node-Derived Stromal Cell Line

Tertiary lymphoid structures (TLSs) associate with better prognosis in certain cancer types, but their underlying formation and immunological benefit remain to be determined. We established a mouse model of TLSs to study their contribution to antitumor immunity. Because the stroma in lymph nodes (sLN) participates in architectural support, lymphogenesis, and lymphocyte recruitment, we hypothesized that TLSs can be created by sLN. We selected a sLN line with fibroblast morphology that expressed sLN surface markers and lymphoid chemokines. The subcutaneous injection of the sLN line successfully induced TLSs that attracted infiltration of host immune cell subsets. Injection of MC38 tumor lysate-pulsed dendritic cells activated TLS-residing lymphocytes to demonstrate specific cytotoxicity. The presence of TLSs suppressed MC38 tumor growth in vivo by improving antitumor activity of tumor-infiltrating lymphocytes with downregulated immune checkpoint proteins (PD-1 and Tim-3). Future engineering of sLN lines may allow for further enhancements of TLS functions and immune cell compositions.