Gene immunization comprises mRNA and DNA vaccines, which stand out due to their simple design, maintenance, and high efficacy. Several studies indicate promising results in preclinical and clinical trials regarding immunization against ebola, human immunodeficiency virus (HIV), influenza, and human papillomavirus (HPV). The efficiency of nucleic acid vaccines has been highlighted in the fight against COVID-19 with unprecedented approval of their use in humans. However, their low intrinsic immunogenicity points to the need to use strategies capable of overcoming this characteristic and increasing the efficiency of vaccine campaigns. These strategies include the improvement of the epitopes’ presentation to the system via MHC, the evaluation of immunodominant epitopes with high coverage against emerging viral subtypes, the use of adjuvants that enhance immunogenicity, and the increase in the efficiency of vaccine transfection. In this review, we provide updates regarding some characteristics, construction, and improvement of such vaccines, especially about the production of synthetic multi-epitope genes, widely employed in the current gene-based vaccines.

In the last decades, technological advances related to RNA manipulation enabled and expanded its application in vaccine development. This approach comprises synthetic single-stranded mRNA molecules that direct the translation of the antigen responsible for activating the desired immune response. The success of RNA vaccines depends on the delivery vehicle employed. Among the systems, yeasts emerge as a new approach to a natural delivery platform. The presence of β-glucans and mannans in its wall is responsible for the adjuvant action of this system. Yeasts are already employed to deliver protein antigens, with success and efficacy demonstrated through pre-clinical and clinical trials. Yeast β-glucan capsules, microparticles, and nanoparticles are capable of modulating host immune responses and have a high capacity to carry RNA and small molecules, with bioavailability upon oral immunization and with targeting to receptors present in anti-gen-presenting cells (APCs). Besides, yeasts are interesting vehicles for the protection and specific delivery of therapeutic vaccines based on shRNA or dsRNA. In this review, we present an overview of the attributes of yeast or its derivatives for the delivery of RNA-based vaccines, discussing their current challenges and prospects for using this promising strategy.

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The understanding of the relationship between immunological responses and cancers, especially those related to HPV, has allowed for the study and development of therapeutic vaccines against these neoplasias. There is a growing number of studies about the composition and influence of the tumor microenvironment (TME) in the progression or establishment of the most varied types of cancer. Hence, it has been possible to structure immunotherapy approaches based on therapeutic vaccines that are even more specific and directed to components of TME and the immune response associated with tumors. Among these components are dendritic cells (DCs), which are the main professional antigen-presenting cells (APCs) already studied in therapy strategies for HPV-related cancers. On the other hand, tumor-associated macrophages are also potential targets since the profile present in tumor infiltrates, M1 or M2, influences the prognosis of some types of cancer. These two cell types can be targets for therapy or immunomodulation. In this context, our review aims to provide an overview of immunotherapy strategies for HPV-positive tumors, such as cervical and head and neck cancers, pointing to TME immune cells as promising targets for these approaches. This review also explores the potential of immunotherapy in cancer treatment, including checkpoint inhibitors, cytokine immunotherapies, immunotherapy vaccines, and cell therapies. Furthermore, it highlights the importance of understanding the TME and its effect on the design and achievement of immunotherapeutic methods.