Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2018 Apr 3;115(14):E3106-E3115. doi: 10.1073/pnas.1718341115. Epub 2018 Mar 19.

Immunization with outer membrane vesicles displaying conserved surface polysaccharide antigen elicits broadly antimicrobial antibodies.

Author information

1
Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853.
2
Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115.
3
Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853.
4
Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853.
5
Department of Microbiology, University of Iowa, Iowa City, IA 52242.
6
Genetics Program, University of Iowa, Iowa City, IA 52242.
7
Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853; md255@cornell.edu.

Abstract

Many microbial pathogens produce a β-(1→6)-linked poly-N-acetyl-d-glucosamine (PNAG) surface capsule, including bacterial, fungal, and protozoan cells. Broadly protective immune responses to this single conserved polysaccharide antigen in animals are possible but only when a deacetylated poly-N-acetyl-d-glucosamine (dPNAG; <30% acetate) glycoform is administered as a conjugate to a carrier protein. Unfortunately, conventional methods for natural extraction or chemical synthesis of dPNAG and its subsequent conjugation to protein carriers can be technically demanding and expensive. Here, we describe an alternative strategy for creating broadly protective vaccine candidates that involved coordinating recombinant poly-N-acetyl-d-glucosamine (rPNAG) biosynthesis with outer membrane vesicle (OMV) formation in laboratory strains of Escherichia coli The glycosylated outer membrane vesicles (glycOMVs) released by these engineered bacteria were decorated with the PNAG glycopolymer and induced high titers of PNAG-specific IgG antibodies after immunization in mice. When a Staphylococcus aureus enzyme responsible for PNAG deacetylation was additionally expressed in these cells, glycOMVs were generated that elicited antibodies to both highly acetylated PNAG (∼95-100% acetate) and a chemically deacetylated dPNAG derivative (∼15% acetate). These antibodies mediated efficient in vitro killing of two distinct PNAG-positive bacterial species, namely S. aureus and Francisella tularensis subsp. holarctica, and mice immunized with PNAG-containing glycOMVs developed protective immunity against these unrelated pathogens. Collectively, our results reveal the potential of glycOMVs for targeting this conserved polysaccharide antigen and engendering protective immunity against the broad range of pathogens that produce surface PNAG.

KEYWORDS:

glycoconjugate vaccine; immunization; infectious disease; oligosaccharide; synthetic biology

PMID:
29555731
PMCID:
PMC5889644
DOI:
10.1073/pnas.1718341115
[Indexed for MEDLINE]
Free PMC Article

Conflict of interest statement

Conflict of interest statement: C.C.-B. is an inventor of intellectual properties (use of human mAb to PNAG and use of PNAG vaccines) that are licensed by Brigham and Women’s Hospital to Alopexx Vaccine, LLC, and Alopexx Pharmaceuticals, LLC. As an inventor of intellectual properties, C.C.-B. also has the right to receive a share of licensing-related income (royalties, fees) through Brigham and Women’s Hospital from Alopexx Pharmaceuticals, LLC, and Alopexx Vaccine, LLC. D.P. and M.P.D. have a financial interest in Versatope, Inc., and M.P.D. also has a financial interest in Glycobia, Inc. The interests of D.P. and M.P.D. are reviewed and managed by Cornell University in accordance with their conflict of interest policies. G.B.P. is an inventor of intellectual properties (human mAb to PNAG and PNAG vaccines) that are licensed by Brigham and Women’s Hospital to Alopexx Vaccine, LLC, and Alopexx Pharmaceuticals, LLC, entities, in which G.B.P. also holds equity. As an inventor of intellectual properties, G.B.P. also has the right to receive a share of licensing-related income (royalties, fees) through Brigham and Women’s Hospital from Alopexx Pharmaceuticals, LLC, and Alopexx Vaccine, LLC. The interests of G.B.P. are reviewed and managed by Brigham and Women’s Hospital and Partners Healthcare in accordance with their conflict of interest policies.

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center