Leveraging a powerful allogeneic dendritic cell line towards neoantigen-based cancer vaccines

Cancer vaccines: platforms and current progress

Cancer vaccines, crucial in the immunotherapeutic landscape, are bifurcated into preventive and therapeutic types, both integral to combating oncogenesis. Preventive cancer vaccines, like those against HPV and HBV, reduce the incidence of virus-associated cancers, while therapeutic cancer vaccines aim to activate dendritic cells and cytotoxic T lymphocytes for durable anti-tumor immunity. Recent advancements in vaccine platforms, such as synthetic peptides, mRNA, DNA, cellular, and nano-vaccines, have enhanced antigen presentation and immune activation. Despite the US Food and Drug Administration approval for several vaccines, the full therapeutic potential remains unrealized due to challenges such as antigen selection, tumor-mediated immunosuppression, and optimization of delivery systems. This review provides a comprehensive analysis of the aims and implications of preventive and therapeutic cancer vaccine, the innovative discovery of neoantigens enhancing vaccine specificity, and the latest strides in vaccine delivery platforms. It also critically evaluates the role of adjuvants in enhancing immunogenicity and mitigating the immunosuppressive tumor microenvironment. The review further examines the synergistic potential of combining cancer vaccines with other therapies, such as chemotherapy, radiotherapy, and immune checkpoint inhibitors, to improve therapeutic outcomes. Overcoming barriers such as effective antigen identification, immunosuppressive microenvironments, and adverse effects is critical for advancing vaccine development. By addressing these challenges, cancer vaccines can offer significant improvements in patient outcomes and broaden the scope of personalized cancer immunotherapy.

Trial watch: anticancer vaccination with dendritic cells

Dendritic cells (DCs) are critical players at the intersection of innate and adaptive immunity, making them ideal candidates for anticancer vaccine development. DC-based immunotherapies typically involve isolating patient-derived DCs, pulsing them with tumor-associated antigens (TAAs) or tumor-specific antigens (TSAs), and utilizing maturation cocktails to ensure their effective activation. These matured DCs are then reinfused to elicit tumor-specific T-cell responses. While this approach has demonstrated the ability to generate potent immune responses, its clinical efficacy has been limited due to the immunosuppressive tumor microenvironment. Recent efforts have focused on enhancing the immunogenicity of DC-based vaccines, particularly through combination therapies with T cell-targeting immunotherapies. This Trial Watch summarizes recent advances in DC-based cancer treatments, including the development of new preclinical and clinical strategies, and discusses the future potential of DC-based vaccines in the evolving landscape of immuno-oncology.

Development of a New Off-the-Shelf Plasmacytoid Dendritic Cell-Based Approach for the Expansion and Characterization of SARS-CoV-2-Specific T Cells

Global vaccination against COVID-19 has been widely successful; however, there is a need for complementary immunotherapies in severe forms of the disease and in immunocompromised patients. Cytotoxic CD8+ T cells have a crucial role in disease control, but their function can be dysregulated in severe forms of the disease. We report here a cell-based approach using a plasmacytoid dendritic cell line (PDC*line) to expand in vitro specific CD8+ responses against COVID-19 Ags. We tested the immunogenicity of eight HLA-A*02:01 restricted peptides derived from diverse SARS-Cov-2 proteins, selected by bioinformatics analyses in unexposed and convalescent donors. Higher ex vivo frequencies of specific T cells against these peptides were found in convalescent donors compared with unexposed donors, suggesting in situ T cell expansion upon viral infection. The peptide-loaded PDC*line induced robust CD8+ responses with total amplification rates that led up to a 198-fold increase in peptide-specific CD8+ T cell frequencies for a single donor. Of note, six of eight selected peptides provided significant amplifications, all of which were conserved between SARS-CoV variants and derived from the membrane, the spike protein, the nucleoprotein, and the ORF1ab. Amplified and cloned antiviral CD8+ T cells secreted IFN-γ upon peptide-specific activation. Furthermore, specific TCR sequences were identified for two highly immunogenic Ags. Hence, PDC*line represents an efficient platform to identify immunogenic viral targets for future immunotherapies.

Recent Advancement of PD-L1 Detection Technologies and Clinical Applications in the Era of Precision Cancer Therapy

Programmed death-1 is a protein found on the surface of immune cells that can interact with its ligand, programmed death-ligand 1 (PD-L1), which is expressed on the plasma membrane, the surface of secreted cellular exosomes, in cell nuclei, or as a circulating soluble protein. This interaction can lead to immune escape in cancer patients. In clinical settings, PD-L1 plays an important role in tumor disease diagnosis, determining therapeutic effectiveness, and predicting patient prognosis. PD-L1 inhibitors are also essential components of tumor immunotherapy. Thus, the detection of PD-L1 levels is crucial, especially in the era of precision cancer therapy. In recent years, innovations have been made in traditional immunoassay methods and the development of new immunoassays for PD-L1 detection. This review aims to summarize recent research progress in tumor PD-L1 detection technology and highlight the clinical applications of PD-L1.