Improved thermal stabilization of VSV-vector with enhanced vacuum drying in pullulan and trehalose-based films.

One major limitation of effective vaccine delivery is its dependency on a robust cold chain infrastructure. While Vesicular stomatitis virus (VSV) has been demonstrated to be an effective viral vaccine vector for diseases including Ebola, its -70 °C storage requirement is a significant limitation for accessing disadvantaged locations and populations. Previous work has shown thermal stabilization of viral vaccines with a combination of pullulan and trehalose (PT) dried films.

CRISPR-mediated rapid arming of poxvirus vectors enables facile generation of the novel immunotherapeutic STINGPOX.

Poxvirus vectors represent versatile modalities for engineering novel vaccines and cancer immunotherapies. In addition to their oncolytic capacity and immunogenic influence, they can be readily engineered to express multiple large transgenes. However, the integration of multiple payloads into poxvirus genomes by traditional recombination-based approaches can be highly inefficient, time-consuming and cumbersome.

Natural killer T cell immunotherapy combined with IL-15-expressing oncolytic virotherapy and PD-1 blockade mediates pancreatic tumor regression.

Background: Pancreatic cancer is one of the leading causes of cancer death, with a 5-year -year survival rate of less than 10%. This results from late detection, high rates of metastasis, and resistance to standard chemotherapies. Furthermore, chemotherapy and radiation are associated with significant morbidity, underscoring the need for novel therapies.

Aerosol delivery, but not intramuscular injection, of adenovirus-vectored tuberculosis vaccine induces respiratory-mucosal immunity in humans.

BackgroundAdenovirus-vectored (Ad-vectored) vaccines are typically administered via i.m. injection to humans and are incapable of inducing respiratory mucosal immunity.

CXCR6 by increasing retention of memory CD8 T cells in the ovarian tumor microenvironment promotes immunosurveillance and control of ovarian cancer.

Purpose: Resident memory CD8 T cells, owing to their ability to reside and persist in peripheral tissues, impart adaptive sentinel activity and amplify local immune response, and have beneficial implications for tumor surveillance and control. The current study aimed to clarify the less known chemotactic mechanisms that govern the localization, retention, and residency of memory CD8 T cells in the ovarian tumor microenvironment.

Experimental Design: RNA and protein expressions of chemokine receptors in CD8 resident memory T cells in human ovarian tumor-infiltrating CD8 T cells and their association with survival were analyzed.

Synergistic anti-tumor efficacy of oncolytic influenza viruses and B7-H3 immune- checkpoint inhibitors against IC-resistant lung cancers.

Non-small cell lung cancers (NSCLCs) establish a highly immunosuppressive tumor microenvironment supporting cancer growth. To interfere with cancer-mediated immunosuppression, selective immune-checkpoint inhibitors (ICIs) have been approved as a standard-of-care treatment for NSCLCs. However, the majority of patients poorly respond to ICI-based immunotherapies.

Immunological considerations for COVID-19 vaccine strategies.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the most formidable challenge to humanity in a century. It is widely believed that prepandemic normalcy will never return until a safe and effective vaccine strategy becomes available and a global vaccination programme is implemented successfully. Here, we discuss the immunological principles that need to be taken into consideration in the development of COVID-19 vaccine strategies.

Enhanced immunotherapeutic profile of oncolytic virus-based cancer vaccination using cyclophosphamide preconditioning.

Despite a sizeable body of research, the efficacy of therapeutic cancer vaccines remains limited when applied as sole agents. By using a prime:boost approach involving two viral cancer vaccines, we were able to generate large tumor-specific CD8 T-cell responses in a murine model of disseminated pulmonary melanoma. Significant increases in the number and quality of circulating effector T-cells were documented when low-dose cyclophosphamide (CTX) was administered pre-vaccination to tumor-bearing but not tumor-free hosts.

Spray dried VSV-vectored vaccine is thermally stable and immunologically active in vivo.

Effective vaccine delivery and coverage to rural and resource-poor countries is hindered by the dependence on cold chain storage. As such, developments of cold chain-free technologies are highly sought. Although spray dried adenoviral vectors have shown long term stability at ambient temperatures and relatively low humidity, it remains to be determined whether similar excipient formulations are applicable to other viral vectors.

Measles Vaccines Designed for Enhanced CD8 T Cell Activation.

Priming and activation of CD8 T cell responses is crucial to achieve anti-viral and anti-tumor immunity. Live attenuated measles vaccine strains have been used successfully for immunization for decades and are currently investigated in trials of oncolytic virotherapy. The available reverse genetics systems allow for insertion of additional genes, including heterologous antigens.

Endogenous T cells prevent tumor immune escape following adoptive T cell therapy.

While the outcome of adoptive T cell therapy (ACT) is typically correlated with the functionality of the inoculated T cells, the role of the endogenous T cells is unknown. The success of checkpoint blockade therapy has demonstrated the potentially curative value of preexisting tumor-primed T cells in cancer treatment. Given the results from checkpoint blockade therapy, we hypothesized that endogenous T cells contribute to long-term survival following ACT.

Detection of Tumor Antigen-Specific T-Cell Responses After Oncolytic Vaccination.

Oncolytic vaccines, which consist of recombinant oncolytic viruses (OV) encoding tumor-associated antigens (TAAs), have demonstrated potent antitumor efficacy in preclinical models and are currently evaluated in phase I/II clinical trials. On one hand, oncolysis of OV-infected malignant entities reinstates cancer immunosurveillance. On the other hand, overexpression of TAAs in infected cells further stimulates the adaptive arm of antitumor immunity.

Oncolytic Maraba virus armed with tumor antigen boosts vaccine priming and reveals diverse therapeutic response patterns when combined with checkpoint blockade in ovarian cancer.

Background: Cancer immunotherapies are emerging as promising treatment strategies for ovarian cancer patients that experience disease relapse following first line therapy. As such, identifying strategies to bolster anti-tumor immunity and limit immune suppression, while recognizing diverse patterns of tumor response to immunotherapy is critical to selecting treatment combinations that lead to durable therapeutic benefit.

Methods: Using a pre-clinical mouse model, we evaluated a heterologous prime/boost vaccine in combination with checkpoint blockade to treat metastatic intraperitoneal ovarian cancer.

Excipient selection for thermally stable enveloped and non-enveloped viral vaccine platforms in dry powders.

Two enveloped viral vectors, vesicular stomatitis virus and influenza virus, and a non-enveloped viral vector, human adenovirus type 5, were encapsulated by spray drying to enhance thermal stability.Results with these candidates led to the hypothesis that stability performance of chosen excipients may be less virus-specific, as previously postulated in the literature, and more differentiated based on whether the virus has a lipid envelope. Spray dried samples were characterized for their thermal properties, RNA viability and in vitro viral activity after storage at 37 °C for up to 30 days or at 45 °C for up to 3 days.

Preclinical evaluation of a MAGE-A3 vaccination utilizing the oncolytic Maraba virus currently in first-in-human trials.

Multiple immunotherapeutics have been approved for cancer patients, however advanced solid tumors are frequently refractory to treatment. We evaluated the safety and immunogenicity of a vaccination approach with multimodal oncolytic potential in non-human primates (NHP) (). Primates received a replication-deficient adenoviral prime, boosted by the oncolytic Maraba MG1 rhabdovirus.

Development and applications of oncolytic Maraba virus vaccines.

Oncolytic activity of the MG1 strain of the Maraba vesiculovirus has proven efficacy in numerous preclinical cancer models, and relied not only on a direct cytotoxicity but also on the induction of both innate and adaptive antitumor immunity. To further expand tumor-specific T-cell effector and long-lasting memory compartments, we introduced the MG1 virus in a prime-boost cancer vaccine strategy. To this aim, a replication-incompetent adenoviral [Ad] vector together with the oncolytic MG1 have each been armed with a transgene expressing a same tumor antigen.

Transforming the prostatic tumor microenvironment with oncolytic virotherapy.

Prostate cancer (PCa) was estimated to have the second highest global incidence rate for male non-skin tumors and is the fifth most deadly in men thus mandating the need for novel treatment options. MG1-Maraba is a potent and versatile oncolytic virus capable of lethally infecting a variety of prostatic tumor cell lines alongside primary PCa biopsies and exerts direct oncolytic effects against large TRAMP-C2 tumors . An oncolytic immunotherapeutic strategy utilizing a priming vaccine and intravenously administered MG1-Maraba both expressing the human six-transmembrane antigen of the prostate (STEAP) protein generated specific CD8+ T-cell responses against multiple STEAP epitopes and resulted in functional breach of tolerance.

Consecutive Spray Drying to Produce Coated Dry Powder Vaccines Suitable for Oral Administration.

Current global vaccination programs are challenged by costs associated with vaccine cold chain storage and administration. A solid, thermally stable oral dosage form for vaccines would alleviate these costs but is difficult to produce due to general vaccine instability and the complication of bypassing the gastric barrier. We developed a novel consecutive spray drying method that is suitable for use with biologics and employs Eudragit L100 polymer as the enteric coating.

Oncolytic influenza virus infection restores immunocompetence of lung tumor-associated alveolar macrophages.

Non-small-cell lung cancer (NSCLC) is the most frequent type of lung cancer and demonstrates high resistance to radiation and chemotherapy. These tumors evade immune system detection by promoting an immunosuppressive tumor microenvironment. Genetic analysis has revealed oncogenic activation of the Ras/Raf/MEK/ERK signaling pathway to be a hallmark of NSCLCs, which promotes influenza A virus (IAV) infection and replication in these cells.

Preclinical development of peptide vaccination combined with oncolytic MG1-E6E7 for HPV-associated cancer.

Human papilloma virus (HPV)-associated cancer is a significant global health burden and despite the presence of viral transforming antigens within neoplastic cells, therapeutic vaccinations are ineffective for advanced disease. HPV positive TC1 cells are susceptible to viral oncolysis by MG1-E6E7, a custom designed oncolytic Maraba virus. Epitope mapping of mice vaccinated with MG1-E6E7 enabled the rational design of synthetic long peptide (SLP) vaccines against HPV16 and HPV18 antigens.

Neoadjuvant oncolytic virotherapy before surgery sensitizes triple-negative breast cancer to immune checkpoint therapy.

Triple-negative breast cancer (TNBC) is an aggressive disease for which treatment options are limited and associated with severe toxicities. Immunotherapeutic approaches like immune checkpoint inhibitors (ICIs) are a potential strategy, but clinical trials have demonstrated limited success in this patient cohort. Clinical studies using ICIs have revealed that patients with preexisting anticancer immunity are the most responsive.

Maraba virus-vectored cancer vaccines represent a safe and novel therapeutic option for cats.

Direct killing of malignant cells combined with induction of tumour-specific immune responses makes oncolytic vaccines attractive for cancer therapy. We previously developed a heterologous cancer immunization strategy that utilized a replication-defective adenovirus-vectored primary vaccine encoding a tumour antigen followed by boosting with a replication-competent Maraba virus expressing the same antigen. To assess the safety of oncolytic Maraba virus-based booster vaccines and inform the design of clinical trials, we conducted translational studies in cats, which have immune systems that are similar to people and spontaneously develop cancers of comparable types and etiologies.

Customized Viral Immunotherapy for HPV-Associated Cancer.

The viral-transforming proteins E6 and E7 make human papillomavirus-positive (HPV) malignancies an attractive target for cancer immunotherapy. However, therapeutic vaccination exerts limited efficacy in the setting of advanced disease. We designed a strategy to induce substantial specific immune responses against multiple epitopes of E6 and E7 proteins based on an attenuated transgene from HPV serotypes 16 and 18 that is incorporated into MG1-Maraba virotherapy (MG1-E6E7).