title: Effects of adsorption to aluminum salt adjuvants on the structure and stability of model protein antigens.
abstract: The effect of adsorption onto aluminum salt adjuvants on the structure and stability of three model protein antigens was studied using fluorescence and Fourier transform infrared spectroscopies, as well as isothermal titration and differential scanning calorimetric techniques. Lysozyme was preferentially adsorbed to aluminum phosphate (Adju-Phos), whereas ovalbumin and bovine serum albumin were better adsorbed to aluminum hydroxide (Alhydrogel). A linearized Langmuir adsorption isotherm was used to obtain information regarding the binding interactions between proteins and adjuvants. Binding energetics and stoichiometry data obtained from isothermal titration calorimetry measurements were complex. Based on the spectroscopic and differential scanning calorimetry studies, the structure of all three proteins, when adsorbed to the surface of an aluminum salt, was altered in such a way as to render the proteins less thermally stable. Besides the pharmaceutical significance of this destabilization, we consider the possibility that this phenomenon may facilitate the presentation of antigens and thus contribute to the adjuvant activity of the aluminum salts.
authors.affiliation: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047, USA. LaToya.Jones@UCHSC.edu
authors.forename: LaToya S
authors.initials: LS
authors.lastname: Jones
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Peek
authors.forename: Jonathan
authors.initials: J
authors.lastname: Power
authors.forename: Aaron
authors.initials: A
authors.lastname: Markham
authors.forename: Brian
authors.initials: B
authors.lastname: Yazzie
authors.forename: C Russell
authors.initials: CR
authors.lastname: Middaugh
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry* / Q000378:metabolism; D000327:Adsorption; D017607:Aluminum Compounds / Q000737:chemistry*; D000818:Animals; D000941:Antigens / Q000737:chemistry* / Q000378:metabolism; D002151:Calorimetry; D002417:Cattle; D009113:Muramidase / Q000737:chemistry / Q000378:metabolism; D010047:Ovalbumin / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012492:Salts / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism; D013696:Temperature
chemical_list: D000276:Adjuvants, Immunologic; D017607:Aluminum Compounds; D000941:Antigens; D012492:Salts; D012710:Serum Albumin, Bovine; D010047:Ovalbumin; D009113:Muramidase