A Self-Assembling Whole-Cell Vaccine Antigen Presentation Platform

Abstract

Diarrhea is the most common infection in children under the age of five worldwide. In spite of this, only a few vaccines to treat infectious diarrhea exist, and many of the available vaccines are sparingly and sporadically administered. Major obstacles to the development and widespread implementation of vaccination include the ease and cost of production, distribution, and delivery. Here we present a novel, customizable and self-assembling vaccine platform that exploits the bacterial biofilm matrix for antigen presentation. We use this technology to create a proof-of-concept, live-attenuated whole cell vaccine that is boosted by spontaneous association of a secreted protein antigen with the cell surface. Sublingual administration of this live-attenuated vaccine to mice confers protection against challenge and elicits production of antigen-specific stool IgA. The platform presented here enables development of antigen-boosted vaccines that are simple to produce and deliver, addressing many of the obstacles to vaccination against diarrheal diseases. This may also serve as a paradigm for the development of broadly protective, biofilm-based vaccines against other mucosal infections. Diarrheal disease is the most common infection afflicting children worldwide. In resource-poor settings, these infections are correlated with cognitive delay, stunted growth, and premature death. With the development of efficacious, affordable, and easily administered vaccines, such infections could be prevented. While a major focus of biofilm research has been their elimination, here we harness the bacterial biofilm to create a customizable platform for cost-effective, whole cell mucosal vaccines that self-incorporate secreted protein antigens. We use this platform to develop a sublingually administered, live-attenuated prototype vaccine based on This serves not only as a proof-of-concept for a multivalent vaccine against common bacterial enteric pathogens but also as a paradigm for vaccines utilizing other bacterial biofilms to target mucosal infections.

Sublingual Adjuvant Delivery by a Live Attenuated Vibrio cholerae-Based Antigen Presentation Platform

“…These were not significantly different at days 56 and 180 postvaccination for vaccines expressing RΔ-CTB with or without mmCT ( Fig. 4E ) and were comparable to the levels of vaccines previously demonstrated to confer protection against V. cholerae ( 8 ). Furthermore, LPS-specific IgG1 and IgG2a titers were similar between the two vaccines ( Fig.…”

“…In our initial experiments, we used a plasmid encoding RbmA fused to CTB ( 8 ). To adapt our vaccine platform for safe delivery as a live attenuated vaccine, we moved the gene encoding R-CTB from a plasmid to the native RbmA site of a V. cholerae strain lacking both the entire CTX phage and tcpA , the major component of toxin-coregulated pilus (TCP) ( Fig.…”

“…Our laboratory has developed a technology that can transform these live attenuated or inactivated whole-cell cholera vaccines into vaccine platforms. This technology is based on genetic fusion of protein antigens to the biofilm matrix-associated protein RbmA ( 8 ).…”

“…We previously showed that plasmid-based expression of a genetic fusion of CTB to RbmA (R-CTB) resulted in abundant decoration of the cell surface with CTB ( 14 ). Sublingual delivery of such a vaccine elicited a mucosal immune response to CTB and provided passive protection against cholera challenge in an infant mouse model ( 8 ). However, expression of R-CTB from the native chromosomal location of RbmA resulted in decreased surface accumulation and poor immunogenicity.…”

Oral vaccination using microdevices to deliver α-GalCer adjuvanted vaccine afford a mucosal immune response

“…These findings are in line with the trends observed in the local mucosal responses in the present study, however the stimulated responses were not statistically enhanced. A likely cause for the different findings is that Dukoral contains a killed whole-cell antigen, thus benefitting from intrinsic adjuvant traits as opposed to CTH522 [43], [44]. An interesting observation from this study is the stimulation of Th17-cells in PPs, which is not seen in the study by Davitt et al CAF01 is known to induce systemic Th17 responses, that can be pulled into mucosal tissues after local mucosalvaccination.…”