title: A partially purified outer membrane protein VirB9-1 for low-cost nanovaccines against Anaplasma marginale.
abstract: Anaplasma marginale is a devastating tick-borne pathogen causing anaplasmosis in cattle and results in significant economic loss to the cattle industry worldwide. Currently, there is no widely accepted vaccine against A. marginale. New generation subunit vaccines against A. marginale, which are much safer, more efficient and cost-effective, are in great need. The A. marginale outer membrane protein VirB9-1 is a promising antigen for vaccination. We previously have shown that soluble recombinant VirB9-1 protein can be expressed and purified from Escherichia coli and induce a high level of humoral and cellular immunity in mice. In this study, we re-formulated the nanovaccines using the partially-purified VirB9-1 protein as the antigen and hollow nano-size silica vesicles (SV-100) as the adjuvant. We simplified the purification method to obtain the partially-purified antigen VirB9-1 with a six-fold higher yield. The new formulations using the partially-purified VirB9-1 protein achieved higher antibody and cell-mediated immune responses compared to the purified ones. This finding suggests that the partially-purified VirB9-1 protein performs better than the purified ones in the vaccination against A. marginale, and a certain level of contaminants in the protein antigen can be self-adjuvant and boost immunogenicity together with the nanoparticle adjuvant. This may lead to finding a "Goldilocks" level of contaminants. The new nanovaccine formulation using partially-purified antigens along with nanoparticle adjuvants offers an alternative strategy for making cheaper veterinary vaccines.
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, QLD 4072, Australia.
authors.forename: Antonino S
authors.initials: AS
authors.lastname: Cavallaro
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Wibowo
authors.affiliation: Animal Science, Agri-Science Queensland, Department of Agriculture & Fisheries, Dutton Park, QLD 4102, Australia.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, QLD 4072, Australia.
authors.forename: Neena
authors.initials: N
authors.lastname: Mitter
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia.
authors.forename: Chengzhong
authors.initials: C
authors.lastname: Yu
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia. Electronic address: z.chunxia@uq.edu.au.
authors.forename: Chun-Xia
authors.initials: CX
authors.lastname: Zhao
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia. Electronic address: a.middelberg@uq.edu.au.
authors.forename: Anton P J
authors.initials: AP
authors.lastname: Middelberg
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D042322:Anaplasma marginale / Q000276:immunology*; D000712:Anaplasmosis / Q000517:prevention & control*; D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology* / Q000302:isolation & purification; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology* / Q000302:isolation & purification; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D005260:Female; D008810:Mice, Inbred C57BL; D012822:Silicon Dioxide / Q000008:administration & dosage*; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000276:immunology / Q000302:isolation & purification
chemical_list: D000276:Adjuvants, Immunologic; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D022223:Vaccines, Subunit; D012822:Silicon Dioxide
keywords: Aggregates; Anaplasma marginale; Endotoxin; Immunogenicity; Partially-purified antigens; Silica vesicles