Bacterial superglue enables easy development of efficient virus-like particle based vaccines.
BACKGROUND
Virus-like particles (VLPs) represent a significant advance in the development of subunit vaccines, combining high safety and efficacy. Their particulate nature and dense repetitive subunit organization makes them ideal scaffolds for display of vaccine antigens. Traditional approaches for VLP-based antigen display require labor-intensive trial-and-error optimization, and often fail to generate dense antigen display. Here we utilize the split-intein (SpyTag/SpyCatcher) conjugation system to generate stable isopeptide bound antigen-VLP complexes by simply mixing of the antigen and VLP components.


RESULTS
Genetic fusion of SpyTag or SpyCatcher to the N-terminus and/or C-terminus of the Acinetobacter phage AP205 capsid protein resulted in formation of stable, nonaggregated VLPs expressing one SpyCatcher, one SpyTag or two SpyTags per capsid protein. Mixing of spy-VLPs with eleven different vaccine antigens fused to SpyCatcher or SpyTag resulted in formation of antigen-VLP complexes with coupling efficiencies (% occupancy of total VLP binding sites) ranging from 22-88 %. In mice, spy-VLP vaccines presenting the malaria proteins Pfs25 or VAR2CSA markedly increased antibody titer, affinity, longevity and functional efficacy compared to corresponding vaccines employing monomeric proteins. The spy-VLP vaccines also effectively broke B cell self-tolerance and induced potent and durable antibody responses upon vaccination with cancer or allergy-associated self-antigens (PD-L1, CTLA-4 and IL-5).


CONCLUSIONS
The spy-VLP system constitutes a versatile and rapid method to develop highly immunogenic VLP-based vaccines. Our data provide proof-of-concept for the technology's ability to present complex vaccine antigens to the immune system and elicit robust functional antibody responses as well as to efficiently break B cell self-tolerance. The spy-VLP-system may serve as a generic tool for the cost-effective development of effective VLP-vaccines against both infectious- and non-communicable diseases and could facilitate rapid and unbiased screening of vaccine candidate antigens.
Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.|Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.
Susan
S
Thrane
Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.|Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.
Christoph M
CM
Janitzek
Kilimanjaro Clinical Research Institute, KCMC, Moshi, Tanzania.
Sungwa
S
Matondo
Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.|Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.
Mafalda
M
Resende
Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.|Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.
Tobias
T
Gustavsson
ExpreS2ion Biotechnologies, SCION-DTU Science Park, Hørsholm, Denmark.
Willem Adriaan
WA
de Jongh
Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.|Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.|ExpreS2ion Biotechnologies, SCION-DTU Science Park, Hørsholm, Denmark.
Stine
S
Clemmensen
Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
Will
W
Roeffen
Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
Marga
M
van de Vegte-Bolmer
Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
Geert Jan
GJ
van Gemert
Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
Robert
R
Sauerwein
Laboratory of Cellular Oncology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
John T
JT
Schiller
Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.|Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.
Morten A
MA
Nielsen
Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.|Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.
Thor G
TG
Theander
Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark. salanti@sund.ku.dk.|Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark. salanti@sund.ku.dk.
Ali
A
Salanti
Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark. adamsander@gmail.com.|Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark. adamsander@gmail.com.
Adam F
AF
Sander
D000150:Acinetobacter / Q000276:immunology; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D001435:Bacteriophages / Q000276:immunology; D036022:Capsid Proteins / Q000276:immunology; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D014611:Vaccination / Q000379:methods; D058425:Vaccines, Virus-Like Particle / Q000276:immunology*
D000942:Antigens, Bacterial; D036022:Capsid Proteins; D058425:Vaccines, Virus-Like Particle