Clinical testing of a dendritic cell targeted therapeutic vaccine in patients with chronic hepatitis C virus infection

A review of the progress and challenges of developing dendritic-based vaccines against hepatitis B virus (HBV)

Hepatitis B virus (HBV) infections that last a long time are a significant public health problem worldwide. About 254 million people around the world are chronically sick with HBV. Each year, 1.2 million new cases occur, and in 2022, 1.1 million people will die from the disease. So, it has been essential to work on finding ways to treat and avoid HBV. The process of therapeutic vaccination involves giving people a non-infectious form of a virus to start or improve immune reactions specific to HBV. This helps keep HBV infections under control. Dendritic cells (DCs) play a significant part in beginning the adaptive immune response, which could decide how well an HBV infection is treated. DC-based treatment has been looked into for people with chronic HBV (CHB) infection and has shown some sound effects. Vaccines for CHB that use DCs boost antiviral immunity by improving T cells and breaking the immune system's resistance against HBV. In these vaccines, DCs are loaded with HBV antigens (like HBsAg, HBcAg, or peptides) outside of the body and then put back into the patient to make the immune system work better. In conclusion, this DC treatment is a biological therapy method with a good chance of being used. This study examined the different DC-based medicines that can treat and prevent HBV. Finally, we've talked about clinical studies, the current problems, how to fix them, and the future of this vaccine for treating and preventing HBV.

Phase I Trial of a Therapeutic DNA Vaccine for Preventing Hepatocellular Carcinoma from Chronic Hepatitis C Virus (HCV) Infection

Chronic hepatitis C can lead to cirrhosis and hepatocellular carcinoma. We studied the safety and immunogenicity of a novel therapeutic hepatitis C virus (HCV) genotype 1a/1b consensus DNA vaccine, INO-8000, encoding HCV NS3, NS4A, NS4B, and NS5A proteins alone or co-administered with DNA-encoding IL12 (INO-9012), a human cytokine that stimulates cellular immune function, in individuals with chronic hepatitis C. This was a phase I, multisite dose-escalation trial with an expansion cohort evaluating doses of 0, 0.3, 1.0, and 3.0 mg of INO-9012 (IL12 DNA) as an addition to 6.0 mg of (INO-8000; HCV DNA vaccine). Vaccines were administered by intramuscular injection followed by electroporation at study entry and at weeks 4, 12, and 24. HCV-specific CD4+ and CD8+ T-cell immune responses were measured by IFNγ ELISpot and flow cytometry-based assays. Transient, mild-to-moderate injection site reactions unrelated to IL12 DNA dose were common. Increases in HCV-specific IFNγ production occurred in 15/20 (75%) participants. Increases in the frequency of HCV-specific CD4+ and CD8+ T cells occurred at all dose levels, with the greatest increases seen at 1.0 mg of INO-9012. HCV-specific CD8+ and CD4+ T-cell activities increased in 16/18 (89%) and 14/17 (82%) participants with available data, respectively. The vaccine regimen was safe and induced HCV-specific CD4+ and CD8+ cellular immune responses of modest magnitude in most HCV-infected participants. The addition of 1.0 mg of IL12 DNA provided the best enhancement of immune responses. The vaccine regimen had little effect on controlling HCV viremia.

PREVENTION RELEVANCE

The administration of IL12 DNA along with a hepatitis C viral antigen DNA vaccine enhanced the HCV-specific immune responses induced by the vaccine in individuals with chronic hepatitis C, an important cause of hepatocellular carcinoma. IL12 could be an effective adjuvant in vaccines targeting HCV and other oncogenic viruses.

Use of Hu-PBL Mice to Study Pathogenesis of Human-Restricted Viruses

Different humanized mouse models have been developed to study human diseases such as autoimmune illnesses, cancer and viral infections. These models are based on the use of immunodeficient mouse strains that are transplanted with human tissues or human immune cells. Among the latter, mice transplanted with hematopoietic stem cells have been widely used to study human infectious diseases. However, mouse models built upon the transplantation of donor-specific mature immune cells are still under development, especially in the field of viral infections. These models can retain the unique immune memory of the donor, making them suitable for the study of correlates of protection upon natural infection or vaccination. Here, we will review some of these models and how they have been applied to virology research. Moreover, the future applications and the potential of these models to design therapies against human viral infections are discussed.

Developing dendritic cell for SARS-CoV-2 vaccine: Breakthrough in the pandemic

Finding a vaccine that can last a long time and effective against viruses with high mutation rates such as SARS-CoV-2 is still a challenge today. The various vaccines that have been available have decreased in effectiveness and require booster administration. As the professional antigen presenting cell, Dendritic Cells can also activate the immune system, especially T cells. This ability makes dendritic cells have been developed as vaccines for some types of diseases. In SARS-CoV-2 infection, T cells play a vital role in eliminating the virus, and their presence can be detected in the long term. Hence, this condition shows that the formation of T cell immunity is essential to prevent and control the course of the disease. The construction of vaccines oriented to induce strong T cells response can be formed by utilizing dendritic cells. In this article, we discuss and illustrate the role of dendritic cells and T cells in the pathogenesis of SARS-CoV-2 infection and summarizing the crucial role of dendritic cells in the formation of T cell immunity. We arrange the basis concept of developing dendritic cells for SARS-CoV-2 vaccines. A dendritic cell-based vaccine for SARS-CoV-2 has the potential to be an effective vaccine that solves existing problems.

In the era of rapid mRNA-based vaccines: Why is there no effective hepatitis C virus vaccine yet?

Hepatitis C virus (HCV) is responsible for no less than 71 million people chronically infected and is one of the most frequent indications for liver transplantation worldwide. Despite direct-acting antiviral therapies fuel optimism in controlling HCV infections, there are several obstacles regarding treatment accessibility and reinfection continues to remain a possibility. Indeed, the majority of new HCV infections in developed countries occur in people who inject drugs and are more plausible to get reinfected. To achieve global epidemic control of this virus the development of an effective prophylactic or therapeutic vaccine becomes a must. The coronavirus disease 19 (COVID-19) pandemic led to auspicious vaccine development against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus, which has renewed interest on fighting HCV epidemic with vaccination. The aim of this review is to highlight the current situation of HCV vaccine candidates designed to prevent and/or to reduce HCV infectious cases and their complications. We will emphasize on some of the crossroads encountered during vaccine development against this insidious virus, together with some key aspects of HCV immunology which have, so far, hampered the progress in this area. The main focus will be on nucleic acid-based as well as recombinant viral vector-based vaccine candidates as the most novel vaccine approaches, some of which have been recently and successfully employed for SARS-CoV-2 vaccines. Finally, some ideas will be presented on which methods to explore for the design of live-attenuated vaccines against HCV.

Genetically Modified Mouse Mesenchymal Stem Cells Expressing Non-Structural Proteins of Hepatitis C Virus Induce Effective Immune Response

Hepatitis C virus (HCV) is one of the major causes of chronic liver disease and leads to cirrhosis and hepatocarcinoma. Despite extensive research, there is still no vaccine against HCV. In order to induce an immune response in DBA/2J mice against HCV, we obtained modified mouse mesenchymal stem cells (mMSCs) simultaneously expressing five nonstructural HCV proteins (NS3-NS5B). The innate immune response to mMSCs was higher than to DNA immunization, with plasmid encoding the same proteins, and to naïve unmodified MSCs. mMSCs triggered strong phagocytic activity, enhanced lymphocyte proliferation, and production of type I and II interferons. The adaptive immune response to mMSCs was also more pronounced than in the case of DNA immunization, as exemplified by a fourfold stronger stimulation of lymphocyte proliferation in response to HCV, a 2.6-fold higher rate of biosynthesis, and a 30-fold higher rate of secretion of IFN-γ, as well as by a 40-fold stronger production of IgG2a antibodies to viral proteins. The immunostimulatory effect of mMSCs was associated with pronounced IL-6 secretion and reduction in the population of myeloid derived suppressor cells (MDSCs). Thus, this is the first example that suggests the feasibility of using mMSCs for the development of an effective anti-HCV vaccine.

Immunotherapy with interferon-α-induced dendritic cells for chronic HCV infection (the results of pilot clinical trial)

The key role of T cells in hepatitis C virus (HCV) elimination and the ability of dendritic cells (DCs) to induce antiviral T cell responses suggest that DC vaccines could be a promising approach in the treatment of chronic HCV infection. The aim of our study was to evaluate, whether immunotherapy with DCs is safe and elicits anti-HCV T cell responses. Ten patients with HCV (genotype 1) were vaccinated with monocyte-derived DCs, generated in the presence of IFN-α (IFN-DCs) and pulsed with recombinant HCV Core and NS3 proteins. Treatment schedule included four subcutaneous vaccinations with 1 week interval and six vaccinations with month interval. No serious adverse events or an increase in hepatitis C biochemical activity were registered after vaccination. Using ex vivo assays for the detection of proliferative responses, IFN-γ production and CD8⁺ degranulation have shown that immunotherapy elicited antigen-specific responses in all patients although individual heterogeneity existed within their types, magnitude, and timing. Core/NS3-specific proliferative response and CD8⁺ T cell degranulation have already been registered after the first course of vaccination. Of note, Core-specific responses had higher magnitude. The appearance of antigen-specific IFN-γ responses was registered after the second vaccination course. Vaccination did not cause Th2 response and expansion of the CD4⁺CD25⁺CD127^- regulatory T cells. Generated immune responses failed to provide virus elimination. Nevertheless, there were inverse correlations between viral load and NS3-specific proliferation (R _S = 0.62; p = 0.05) and IFN-γ secretion (R _S = - 0.82; p = 0.001) at 6-month post-treatment period. Immunotherapy with IFN-DCs was safe and elicited HCV-specific T cell responses which were insufficient to eliminate viruses but could be implicated in the restriction of viral replication.

Enhancement of Antitumor Vaccination by Targeting Dendritic Cell-Related IL-10

Understanding mechanisms associated to dendritic cell (DC) functions has allowed developing new antitumor therapeutic vaccination strategies. However, these vaccines have demonstrated limited clinical results. Although the low immunogenicity of tumor antigens used and the presence of tumor-associated suppressive factors may in part account for these results, intrinsic vaccine-related factors may also be involved. Vaccines modulate DC functions by inducing activating and inhibitory signals that determine ensuing T cell responses. In this mini review, we focus on IL-10, inhibitory cytokine induced in DC upon vaccination, which defines a suppressive cell subset, discussing its implications as a potential target in combined vaccination immunotherapies.

Automated generation of immature dendritic cells in a single-use system

Dendritic cells (DCs) are an indispensable part of studying human responses that are important for protective immunity against cancer and infectious diseases as well as prevention of autoimmunity and transplant rejection. These cells are also key elements of personalized vaccines for cancer and infectious diseases. Despite the vital role of DCs in both clinical and basic research contexts, methods for obtaining these cells from individuals remains a comparatively under-developed and inefficient process. DCs are present in very low concentrations (<1%) in blood, thus they must be generated from monocytes and the current methodology in DC generation involves a laborious process of static culture and stimulation with cytokines contained in culture medium. Herein, we describe an automated fluidic system, MicroDEN, that allows for differentiation of monocytes into immature-DCs (iDCs) utilizing continuous perfusion of differentiation media. Manual steps associated with current ex vivo monocyte differentiation are vastly reduced and an aseptic environment is ensured by the use of an enclosed cartridge and tubing network. Benchmark phenotyping was performed on the generated iDCs along with allogeneic T-cell proliferation and syngeneic antigen-specific functional assays. MicroDEN generated iDCs were phenotypically and functionally similar to well plate generated iDCs, thereby demonstrating the feasibility of utilizing MicroDEN in the broad range of applications requiring DCs.

TLR9-Mediated Conditioning of Liver Environment Is Essential for Successful Intrahepatic Immunotherapy and Effective Memory Recall

Immune defense against hepatotropic viruses such as hepatitis B (HBV) and hepatitis C (HCV) poses a major challenge for therapeutic approaches. Intrahepatic cytotoxic CD8 T cells that are crucial for an immune response against these viruses often become exhausted resulting in chronic infection. We elucidated the T cell response upon therapeutic vaccination in inducible transgenic mouse models in which variable percentages of antigen-expressing hepatocytes can be adjusted, providing mosaic antigen distribution and reflecting the varying viral antigen loads observed in patients. Vaccination-induced endogenous CD8 T cells could eliminate low antigen loads in liver but were functionally impaired if confronted with elevated antigen loads. Strikingly, only by conditioning the liver environment with TLR9 ligand prior and early after peripheral vaccination, successful immunization against high intrahepatic antigen density with its elimination was achieved. Moreover, TLR9 immunomodulation was also indispensable for functional memory recall after high frequency antigen challenge. Together, the results indicate that TLR9-mediated conditioning of liver environment during therapeutic vaccination or antigen reoccurrence is crucial for an efficacious intrahepatic T cell response.

Vaccination with poly(IC:LC) and peptide-pulsed autologous dendritic cells in patients with pancreatic cancer

BACKGROUND

Dendritic cells (DCs) enhance the quality of anti-tumor immune response in patients with cancer. Thus, we posit that DC-based immunotherapy, in conjunction with toll-like receptor (TLR)-3 agonist poly-ICLC, is a promising approach for harnessing immunity against metastatic or locally advanced unresectable pancreatic cancer (PC).

METHODS

We generated autologous DCs from the peripheral blood of HLA-A2+ patients with PC. DCs were pulsed with three distinct A2-restricted peptides: 1) human telomerase reverse transcriptase (hTERT, TERT572Y), 2) carcinoembryonic antigen (CEA; Cap1-6D), and 3) survivin (SRV.A2). Patients received four intradermal injections of 1 × 107 peptide-pulsed DC vaccines every 2 weeks (Day 0, 14, 28, and 42). Concurrently, patients received intramuscular administration of Poly-ICLC at 30 μg/Kg on vaccination days (i.e., day 0, 14, 28, and 42), as well as on days 3, 17, 21, 31, 37, and 45. Our key objective was to assess safety and feasibility. The effect of DC vaccination on immune response was measured at each DC injection time point by enumerating the phenotype and function of patient T cells.

RESULTS

Twelve patients underwent apheresis: nine patients with metastatic disease, and three patients with locally advanced unresectable disease. Vaccines were successfully manufactured from all individuals. We found that this treatment was well-tolerated, with the most common symptoms being fatigue and/or self-limiting flu-like symptoms. Among the eight patients who underwent imaging on day 56, four patients experienced stable disease while four patients had disease progression. The median overall survival was 7.7 months. One patient survived for 28 months post leukapheresis. MHC class I -tetramer analysis before and after vaccination revealed effective generation of antigen-specific T cells in three patients with stable disease.

CONCLUSION

Vaccination with peptide-pulsed DCs in combination with poly-ICLC is safe and induces a measurable tumor specific T cell population in patients with advanced PC.

TRIAL REGISTRATION

NCT01410968 ; Name of registry: clinicaltrials.gov; Date of registration: 08/04/2011).

In vivo stepwise immunomodulation using chitosan nanoparticles as a platform nanotechnology for cancer immunotherapy

Dentritic cell (DC)-based cancer immunotherapy faces challenges in both efficacy and practicality. However, DC-based vaccination requires multiple injections and elaborates ex vivo manipulation, which substantially limits their use. Therefore, we sought to develop a chitosan nanoparticle (CH-NP)-based platform for the next generation of vaccines to bypass the ex vivo manipulation and induce immune responses via active delivery of polyinosinic-polycytidylic acid sodium salt (poly I:C) to target Toll-like receptor 3 (TLR3) in endosomes. We developed CH-NPs encapsulating ovalbumin (OVA) as a model antigen and poly I:C as the adjuvant in an ionic complex. These CH-NPs showed increased in vivo intracellular delivery to the DCs in comparison with controls after injection into tumor-bearing mice, and promoted DC maturation, leading to emergence of antigen-specific cytotoxic CD8+ T cells. Finally, the CH-NPs showed significantly greater antitumor efficacy in EG.7 and TC-1 tumor-bearing mice compared to the control (p < 0.01). Taken together, these data show that the CH-NP platform can be used as an immune response modulatory vaccine for active cancer immunotherapy without ex vivo manipulation, thus resulting in increased anticancer efficacy.

Dendritic cell-based vaccines in treating recurrent herpes labialis: Results of pilot clinical study

Recurrent herpes simplex labialis caused predominantly with herpes simplexvirus 1(HSV-1) is a major problem, for which various treatments have minimal impact. Given the important role of the immune system in controlling virus infection, an activation of virus-specific immune responses, in particular,using dendritic cell (DCs) vaccines, seems to be a promising approach for the treatment of patients with frequent recurrences of herpes labialis. The current paper presents the results of a pilot study of the safety and efficacy of DC vaccines in 14 patients with recurrent HSV-1 infections. DCs were generated in presence of GM-CSF and IFN-alpha and were loaded with HSV-1 recombinant viral glycoprotein D (HSV1gD). DCs cells were injected subcutaneously as 2 courses of vaccination during 9 months. Immunotherapy with DCs did not induce any serious side effects and resulted in more than 2-fold reduction in the recurrence rate and significant enhancement of the inter-recurrent time during the 9 months of treatment and subsequent 6-month follow-up period. An obvious clinical improvement was accompanied with an induction of an antigen-specific response to HCV1gD and a normalization of reduced mitogenic responsiveness of mono-nuclear cells. According to long-term survey data (on average 48 months after the beginning of therapy), 87% of respondents reported the decreased incidence of recurrent infection. At this time, most patients (85.7%) responded to HCV1gD stimulation. The data obtained suggests that dendritic cell vaccines may be a promising new approach for the treatment of recurrent labial herpes.