title: Mechanisms of Antigen Adsorption Onto an Aluminum-Hydroxide Adjuvant Evaluated by High-Throughput Screening.
abstract: The adsorption mechanism of antigen on aluminum adjuvant can affect antigen elution at the injection site and hence the immune response. Our aim was to evaluate adsorption onto aluminum hydroxide (AH) by ligand exchange and electrostatic interactions of model proteins and antigens, bovine serum albumin (BSA), β-casein, ovalbumin (OVA), hepatitis B surface antigen, and tetanus toxin (TT). A high-throughput screening platform was developed to measure adsorption isotherms in the presence of electrolytes and ligand exchange by a fluorescence-spectroscopy method that detects the catalysis of 6,8-difluoro-4-methylumbelliferyl phosphate by free hydroxyl groups on AH. BSA adsorption depended on predominant electrostatic interactions. Ligand exchange contributes to the adsorption of β-casein, OVA, hepatitis B surface antigen, and TT onto AH. Based on relative surface phosphophilicity and adsorption isotherms in the presence of phosphate and fluoride, the capacities of the proteins to interact with AH by ligand exchange followed the trend: OVA < β-casein < BSA < TT. This could be explained by both the content of ligands available in the protein structure for ligand exchange and the antigen's molecular weight. The high-throughput screening platform can be used to better understand the contributions of ligand exchange and electrostatic attractions governing the interactions between an antigen adsorbed onto aluminum-containing adjuvant.
authors.affiliation: Université Catholique de Louvain, Louvain Drug Research Institute, Advanced Drug Delivery and Biomaterials, Brussels 1200, Belgium; GSK Vaccines, Vaccine Discovery and Development, Rixensart 1330, Belgium.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Jully
authors.affiliation: GSK Vaccines, Vaccine Discovery and Development, Rixensart 1330, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Mathot
authors.affiliation: GSK Vaccines, Vaccine Discovery and Development, Rixensart 1330, Belgium.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Moniotte
authors.affiliation: Université Catholique de Louvain, Louvain Drug Research Institute, Advanced Drug Delivery and Biomaterials, Brussels 1200, Belgium. Electronic address: veronique.preat@uclouvain.be.
authors.forename: Véronique
authors.initials: V
authors.lastname: Préat
authors.affiliation: GSK Vaccines, Vaccine Discovery and Development, Rixensart 1330, Belgium.
authors.forename: Dominique
authors.initials: D
authors.lastname: Lemoine
mesh_terms: D000277:Adjuvants, Pharmaceutic / Q000737:chemistry / Q000378:metabolism; D000327:Adsorption; D000536:Aluminum Hydroxide / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D000941:Antigens / Q000032:analysis* / Q000378:metabolism*; D002364:Caseins / Q000032:analysis / Q000378:metabolism; D002417:Cattle; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006514:Hepatitis B Surface Antigens / Q000032:analysis / Q000378:metabolism; D057166:High-Throughput Screening Assays / Q000379:methods*; D006801:Humans; D010047:Ovalbumin / Q000032:analysis / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000032:analysis / Q000378:metabolism; D013745:Tetanus Toxoid / Q000032:analysis / Q000378:metabolism
chemical_list: D000277:Adjuvants, Pharmaceutic; D000941:Antigens; D002364:Caseins; D006514:Hepatitis B Surface Antigens; D013745:Tetanus Toxoid; D012710:Serum Albumin, Bovine; D000536:Aluminum Hydroxide; D010047:Ovalbumin
keywords: adsorption; adsorption isotherm; adsorption mechanisms; aluminum hydroxide; antigen; automation; high-throughput screening; phosphophilicity; vaccine adjuvants; vaccines