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Alharbi N, Shalash AO, Koirala P, Boer JC, Hussein WM, Khalil ZG, Capon RJ, Plebanski M, Toth I, Skwarczynski M. Cholesterol as an inbuilt immunoadjuvant for a lipopeptide vaccine against group A Streptococcus infection. J Colloid Interface Sci 2024; 663:43-52. [PMID: 38387185 DOI: 10.1016/j.jcis.2024.02.134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 01/21/2024] [Accepted: 02/17/2024] [Indexed: 02/24/2024]
Abstract
Peptide-based vaccines can trigger highly specific immune responses, although peptides alone are usually unable to confer strong humoral or cellular immunity. Consequently, peptide antigens are administered with immunostimulatory adjuvants, but only a few are safe and effective for human use. To overcome this obstacle, herein a peptide antigen was lipidated to effectively anchor it to liposomes and emulsion. A peptide antigen B cell epitope from Group A Streptococcus M protein was conjugated to a universal T helper epitope, the pan DR-biding epitope (PADRE), alongside a lipidic moiety cholesterol. Compared to a free peptide antigen, the lipidated version (LP1) adopted a helical conformation and self-assembled into small nanoparticles. Surprisingly, LP1 alone induced the same or higher antibody titers than liposomes or emulsion-based formulations. In addition, antibodies produced by mice immunized with LP1 were more opsonic than those induced by administering the antigen with incomplete Freund's adjuvant. No side effects were observed in the immunized mice and no excessive inflammatory immune responses were detected. Overall, this study demonstrated how simple conjugation of cholesterol to a peptide antigen can produce a safe and efficacious vaccine against Group A Streptococcus - the leading cause of superficial infections and the bacteria responsible for deadly post-infection autoimmune disorders.
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Affiliation(s)
- Nedaa Alharbi
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; University of Jeddah, College of Science, Department of Chemistry, Jeddah, Saudi Arabia
| | - Ahmed O Shalash
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Prashamsa Koirala
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jennifer C Boer
- School of Health and Biomedical Sciences, RMIT University, VIC 3083, Australia
| | - Waleed M Hussein
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Zeinab G Khalil
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Robert J Capon
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Magdalena Plebanski
- School of Health and Biomedical Sciences, RMIT University, VIC 3083, Australia
| | - Istvan Toth
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia; School of Pharmacy, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Mariusz Skwarczynski
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.
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