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Vaccines are a pivotal achievement in public health, offering inexpensive, distributable and highly effective protection against infectious diseases. Despite significant advancements in vaccine development, there are still many diseases for which vaccines are unavailable or offer limited protection. The global impact of the deficiency in vaccine‐induced immunity against these diseases is profound, leading to increased rates of illness, more frequent hospitalizations, and higher mortality rates. Recent studies have demonstrated conjugation mechanisms and delivery methods to co‐present adjuvants and protein epitopes to antigen‐presenting cells, significantly enhancing adaptive immunity. We introduce a novel approach to incorporate an adjuvant into the vaccine by covalently attaching it to whole enveloped virions. Using clickable azide‐enabled viral particles, generated through metabolic incorporation of N‐azidoacetyl glucosamine (GlcNAz), we conjugated the virions with a cyclo‐octyne‐modified CpG‐ODN. Conjugation yielded a potent adjuvant‐virus complex, eliciting higher TLR9‐mediated cell activation of cultured bone marrow‐derived macrophages relative to co‐administered adjuvants and virions. Administration of covalent adjuvant‐virion conjugates increase immune cell stimulation and may provide a generalizable and effective strategy for eliciting a heightened immune response for vaccine development.
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A low-cost recombinant glycoconjugate vaccine confers immunogenicity and protection against enterotoxigenic Escherichia coli infections in mice
Enterotoxigenic Escherichia coli (ETEC) is the primary etiologic agent of traveler’s diarrhea and a major cause of diarrheal disease and death worldwide, especially in infants and young children. Despite significant efforts over the past several decades, an affordable vaccine that appreciably decreases mortality and morbidity associated with ETEC infection among children under the age of 5 years remains an unmet aspirational goal. Here, we describe robust, cost-effective biosynthetic routes that leverage glycoengineered strains of non-pathogenic E. coli or their cell-free extracts for producing conjugate vaccine candidates against two of the most prevalent O serogroups of ETEC, O148 and O78. Specifically, we demonstrate site-specific installation of O-antigen polysaccharides (O-PS) corresponding to these serogroups onto licensed carrier proteins using the oligosaccharyltransferase PglB from Campylobacter jejuni. The resulting conjugates stimulate strong O-PS-specific humoral responses in mice and elicit IgG antibodies that possess bactericidal activity against the cognate pathogens. We also show that one of the prototype conjugates decorated with serogroup O148 O-PS reduces ETEC colonization in mice, providing evidence of vaccine-induced mucosal protection. We anticipate that our bacterial cell-based and cell-free platforms will enable creation of multivalent formulations with the potential for broad ETEC serogroup protection and increased access through low-cost biomanufacturing.
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- PAR ID:
- 10416367
- Date Published:
- Journal Name:
- Frontiers in Molecular Biosciences
- Volume:
- 10
- ISSN:
- 2296-889X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/fmolb.2023.1085887
