Human Enterovirus 71 Protein Displayed on the Surface of Saccharomyces cerevisiae as an Oral Vaccine

Microbe-material hybrids for therapeutic applications

As natural living substances, microorganisms have emerged as useful resources in medicine for creating microbe-material hybrids ranging from nano to macro dimensions. The engineering of microbe-involved nanomedicine capitalizes on the distinctive physiological attributes of microbes, particularly their intrinsic "living" properties such as hypoxia tendency and oxygen production capabilities. Exploiting these remarkable characteristics in combination with other functional materials or molecules enables synergistic enhancements that hold tremendous promise for improved drug delivery, site-specific therapy, and enhanced monitoring of treatment outcomes, presenting substantial opportunities for amplifying the efficacy of disease treatments. This comprehensive review outlines the microorganisms and microbial derivatives used in biomedicine and their specific advantages for therapeutic application. In addition, we delineate the fundamental strategies and mechanisms employed for constructing microbe-material hybrids. The diverse biomedical applications of the constructed microbe-material hybrids, encompassing bioimaging, anti-tumor, anti-bacteria, anti-inflammation and other diseases therapy are exhaustively illustrated. We also discuss the current challenges and prospects associated with the clinical translation of microbe-material hybrid platforms. Therefore, the unique versatility and potential exhibited by microbe-material hybrids position them as promising candidates for the development of next-generation nanomedicine and biomaterials with unique theranostic properties and functionalities.

Saccharomyces cerevisiae cells that display norovirus P induce both systemic and mucosal neutralizing antibodies

The human norovirus (HuNov) is the leading cause of acute gastroenteritis (AGE) worldwide. Mucosal secretory IgA (sIgA) in the gastrointestinal tract interrupts the interaction between host cells and HuNov, thus inhibiting viral infection. In this study, we constructed a recombinant Saccharomyces cerevisiae (S. cerevisiae) expressing the HuNov P protein (GII. 4) and evaluated its immunogenicity in mice after oral delivery. First, the recombinant S. cerevisiae (EBY100/pYD1-P) efficiently expressed P, as evidenced by western blotting and indirect fluorescent assay. Second, after oral administration, EBY100/pYD1-P, especially the high-dose group (5 × 109 clone formation units), elicited systemic and mucosal immune responses characterized by significant sera IgG, IgA, and mucosal sIgA. More importantly, these antibodies showed a substantial neutralization effect against P. Lastly, EBY100/pYD1-P induced significant P-specific IFN-γ-secreting T cells and IL4-secreting T cells. Collectively, the recombinant S. cerevisiae expressing HuNov P is a promising mucosal vaccine candidate against HuNov.

Yeast oral vaccines against infectious diseases

Vaccines that are delivered orally have several advantages over their counterparts that are administered via injection. Despite the advantages of oral delivery, however, approved oral vaccines are currently limited either to diseases that affect the gastrointestinal tract or to pathogens that have a crucial life cycle stage in the gut. Moreover, all of the approved oral vaccines for these diseases involve live-attenuated or inactivated pathogens. This mini-review summarizes the potential and challenges of yeast oral vaccine delivery systems for animal and human infectious diseases. These delivery systems utilize whole yeast recombinant cells that are consumed orally to transport candidate antigens to the immune system of the gut. This review begins with a discussion of the challenges associated with oral administration of vaccines and the distinct benefits offered by whole yeast delivery systems over other delivery systems. It then surveys the emerging yeast oral vaccines that have been developed over the past decade to combat animal and human diseases. In recent years, several candidate vaccines have emerged that can elicit the necessary immune response to provide significant protection against challenge by pathogen. They serve as proof of principle to show that yeast oral vaccines hold much promise.

Oral vaccination using Artemia coated with recombinant Saccharomyces cerevisiae expressing cyprinid herpesvirus-3 envelope antigen induces protective immunity in common carp (Cyprinus carpio var. Jian) larvae

Cyprinid herpesvirus 3 (CyHV-3) is the etiological agent of koi herpersvirus disease (KHVD), which causes serious economic losses in global common carp and ornamental koi carp production of larvae as well as adult type fish. To control KHVD, vaccines against CyHV-3 utilizing different immunization routes have been developed, among them, oral vaccination is the most desirable method to prevent fish diseases occurring at the early larval stage. Here, we developed an oral subunit vaccine through the Saccharomyces cerevisiae cell surface display of CyHV-3 envelope protein pORF65, then, the recombinant yeast fed to Artemia which served as bio-encapsulation vector by subsequently feeding the common carp (Cyprinus carpio var. Jian) larvae. The fluorescent observation showed that the Artemia and S. cerevisiae could deliver intact antigen to the hindgut of carp larvae suggesting the possibility of the vector for oral immunization. On this basis, after three immunizations at a week interval, the oral vaccine induced high level of specific anti-pORF65 antibody. Meanwhile, a significant difference of immune-related genes expression occurred including cxca, IL-1β, IFN-a1, lysozyme, IgM and CD8α between vaccined group and blank control group. In addition, 30% of relative percent survival of carp larvae after immunization was obtained post the animal infection assay, offered an certain immune protection. Our results indicated that the oral pORF65 subunit vaccine bioencapsulated in Artemia induced the activation of immune response and high level of antibodies, which could be served as an oral vaccine candidate for the prevention of CyHV-3 infection.

Antivirals and vaccines for Enterovirus A71

Enterovirus A71 (EV-A71) is an important emerging virus posing a threat to children under five years old. EV-A71 infection in infants or young children can cause hand-foot-and-mouth disease, herpangina, or severe neurological complications. However, there are still no effective antivirals for treatment of these infections. In this review, we summarize the antiviral compounds developed to date based on various targets of the EV-A71 life cycle. Moreover, development of a vaccine would be the most effective approach to prevent EV-A71 infection. Therefore, we also summarize the development and clinical progress of various candidate EV-A71 vaccines, including inactivated whole virus, recombinant VP1 protein, synthetic peptides, viral-like particles, and live attenuated vaccines.

Evaluation of the immunogenicity of an omp A and staphylococcal target of RNAIII activating fusion protein displayed on the surface of Escherichia coli

The purpose of this investigation was to construct a recombinant Escherichia coli strain displaying the Staphylococcus aureus target of RNAIII activating protein (TRAP) on its surface, and to investigate the strain for its immunogenicity. The lpp'ompA and lpp'ompA-TRAP genes were fused by the overlap polymerase chain reaction and then ligated into expression plasmid pQE30 producing pLO and pLO-TRAP. These two recombinant plasmids were transformed into E. coli XL1-Blue, resulting in XL1-Blue/pLO and XL1-Blue/pLO-TRAP, which were induced to express protein. The expressed TRAP protein was displayed on the surface of XL1-Blue as judged by whole cell ELISA, flow cytometric analysis, and laser scanning confocal microscopy using the lpp'ompA surface display system. ICR mice were intramuscularly immunized with recombinant strains XL1-Blue/pLO and XL1-Blue/pLO-TRAP as well as recombinant protein TRAP. Immunized mice were assessed for anti-TRAP antibody and lymphocytes for secreted IL-4 and IFN-γ by ELISPOT and secreted IL-17A by indirect ELISA. Immunized mice were challenged with S. aureus Newman and HLJ23-1 strains. The results showed both XL1-Blue/pLO-TRAP and TRAP protein immunized mice to produce better cellular and humoral immunity than XL1-Blue/pLO and PBS injected mice.