title: Contribution of electrostatic and hydrophobic interactions to the adsorption of proteins by aluminium-containing adjuvants.
abstract: The effect of ionic strength and ethylene glycol on the adsorption of bovine serum albumin (BSA) or lysozyme by a commercial aluminium hydroxide or aluminium phosphate adjuvant was studied at pH 7.4 and 25 degrees C. The adsorption of BSA by aluminium hydroxide adjuvant and lysozyme by aluminium phosphate adjuvant was found to be inversely related to ionic strength. This indicates that electrostatic attractive forces contribute to adsorption. The adsorption of lysozyme by aluminium phosphate adjuvant was reduced by the addition of ethylene glycol. However, no change in the adsorption of BSA by aluminium hydroxide adjuvant was noted when up to 40% ethylene glycol was present. This behaviour indicates that hydrophobic forces contribute to the adsorption of lysozyme but not of BSA. However, virtually no adsorption was observed when the protein and the adjuvant had the same surface charge. Thus, attractive forces may not be sufficient to produce adsorption of an antigen by an aluminium-containing adjuvant if electrostatic repulsive forces are present.
authors.affiliation: Department of Industrial and Physical Pharmacy, Pudue University, West Lafayette, IN 47907, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: al-Shakhshir
authors.forename: F E
authors.initials: FE
authors.lastname: Regnier
authors.forename: J L
authors.initials: JL
authors.lastname: White
authors.forename: S L
authors.initials: SL
authors.lastname: Hem
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry*; D000327:Adsorption; D000535:Aluminum / Q000032:analysis*; D004563:Electrochemistry; D019855:Ethylene Glycol; D005026:Ethylene Glycols / Q000737:chemistry*; D009113:Muramidase / Q000737:chemistry*; D009994:Osmolar Concentration; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012995:Solubility; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D000276:Adjuvants, Immunologic; D005026:Ethylene Glycols; D014867:Water; D012710:Serum Albumin, Bovine; D000535:Aluminum; D009113:Muramidase; D019855:Ethylene Glycol