Oral Vaccines: Challenges, Immunity and Therapeutic Advances

Dear Colleagues,

Oral vaccines represent a transformative approach in immunotherapy, offering non-invasive delivery and the unique ability to stimulate both mucosal and systemic immune responses. However, their clinical translation remains limited by formidable barriers, including degradation by gastric acidity and digestive enzymes, restricted epithelial permeability, and immune tolerance within the gut. Recent advances focus on exploiting the gut-associated lymphoid tissue (GALT), where inductive sites like Peyer’s patches and mesenteric lymph nodes, and effector compartments such as intraepithelial and lamina propria lymphocytes, coordinate antigen-specific responses, most notably the production of secretory IgA and activation of cytotoxic T cells. Simultaneously, systemic immunity, via splenic activation and IgG production, broadens the protective scope.

To overcome physiological hurdles, innovative platforms, including probiotic bacteria, biodegradable nanoparticles, and mucosal adjuvants, are being developed to ensure targeted delivery and enhanced immunogenicity. These strategies are not only improving responses to infectious diseases but are also being repurposed to deliver tumor antigens, opening up novel avenues in cancer immunotherapy. As oral vaccines evolve, they stand at the intersection of microbiology, immunology, and oncology, offering a promising advancement for next-generation therapeutics.

We are pleased to invite you to contribute to this Special Issue, entitled "Oral Vaccines: Challenges, Immunity and Therapeutic Advances". Oral vaccination is gaining increasing attention as a powerful tool for preventing and treating diseases across a wide range of fields, including infectious diseases, cancer immunotherapy, and mucosal immunity. Unlike traditional injectable vaccines, oral vaccines can stimulate both local and systemic immune responses, offering advantages in terms of accessibility, patient compliance, and global health impact. However, their development faces complex scientific challenges, including gastrointestinal degradation, mucosal tolerance, and targeted delivery. Given recent advances in delivery platforms such as nanoparticles and engineered bacteria, this is a timely and important area of research with high translational potential.

This Special Issue aims to gather cutting-edge research and comprehensive reviews that explore the development, immunological mechanisms, and clinical potential of oral vaccines. It aligns with the journal's focus on vaccine science, immunology, and infectious diseases while also embracing novel cross disciplinary strategies from oncology, microbiology, and nanomedicine. By showcasing recent progress and remaining challenges, we hope to foster collaboration and innovation in this dynamic field.

For this Special Issue, original research articles and reviews are welcome to be submitted. Research areas may include, but are not limited to, the following:

• Mucosal immune mechanisms in oral vaccination;
• Oral delivery systems (e.g., nanoparticles, microparticles, liposomes);
• Probiotic or bacterial vectors for vaccine delivery;
• Oral vaccines for infectious diseases (viral, bacterial, parasitic);
• Oral cancer vaccines and tumor antigen delivery;
• Overcoming gastrointestinal barriers in vaccine development;
• Immunoadjuvants and mucosal targeting strategies;
• Comparative studies of oral vs. parenteral immunization.

I look forward to receiving your contributions.

Dr. Amin Safa
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Vaccines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• oral vaccines
• mucosal immunity
• Peyer’s patches
• nanoparticles
• probiotic delivery
• cancer immunotherapy
• gastrointestinal barriers
• antigen presentation