title: Blood stage merozoite surface protein conjugated to nanoparticles induce potent parasite inhibitory antibodies.
abstract: In this proof-of-concept study we report the use of <15 nm, water soluble, inorganic nanoparticles as a vaccine delivery system for a blood stage malaria vaccine. The recombinant malarial antigen, Merozoite Surface Protein 1 (rMSP1) of Plasmodium falciparum served as the model vaccine. The rMSP1 was covalently conjugated to polymer-coated quantum dot CdSe/ZnS nanoparticles (QDs) via surface carboxyl groups, forming rMSP1-QDs. Anti-MSP1 antibody responses induced by rMSP1-QDs were found to have 2-3 log higher titers than those obtained with rMSP1 administered with the conventional adjuvants, Montanide ISA51 and CFA. Moreover, the immune responsiveness and the induction of parasite inhibitory antibodies were significantly superior in mice injected with rMSP1-QDs. The rMSP1-QDs delivered via intra-peritoneal (i.p.), intra-muscular (i.m.), and subcutaneous (s.c.) routes were equally efficacious. The high level of immunogenicity exhibited by the rMSP1-QDs was achieved without further addition of other adjuvant components. Bone marrow derived dendritic cells were shown to efficiently take up the nanoparticles leading to their activation and the expression/secretion of key cytokines, suggesting that this may be a mode of action for the enhanced immunogenicity. This study provides promising results for the use of water soluble, inorganic nanoparticles (<15 nm) as potent vehicles/platforms to enhance the immunogenicity of polypeptide antigens in adjuvant-free immunizations.
authors.affiliation: University of Hawaii, School of Medicine, Department of Tropical Medicine, 651 Ilalo Street, BSB320 Honolulu, HI 96813, USA.
authors.forename: Kae
authors.initials: K
authors.lastname: Pusic
authors.forename: Hengyi
authors.initials: H
authors.lastname: Xu
authors.forename: Andrew
authors.initials: A
authors.lastname: Stridiron
authors.forename: Zoraida
authors.initials: Z
authors.lastname: Aguilar
authors.forename: Andrew
authors.initials: A
authors.lastname: Wang
authors.forename: George
authors.initials: G
authors.lastname: Hui
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D016207:Cytokines / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D007074:Immunoglobulin G / Q000097:blood; D017780:Malaria Vaccines / Q000008:administration & dosage / Q000276:immunology*; D016778:Malaria, Falciparum / Q000276:immunology / Q000517:prevention & control*; D020066:Merozoite Surface Protein 1 / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000008:administration & dosage*; D010963:Plasmodium falciparum / Q000276:immunology; D045663:Quantum Dots; D011994:Recombinant Proteins / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000913:Antibodies, Protozoan; D016207:Cytokines; D007074:Immunoglobulin G; D017780:Malaria Vaccines; D020066:Merozoite Surface Protein 1; D011994:Recombinant Proteins