title: Effects of solution conditions and surface chemistry on the adsorption of three recombinant botulinum neurotoxin antigens to aluminum salt adjuvants.
abstract: Botulinum neurotoxin (BoNT) is a biological warfare threat. Protein antigens have been developed against the seven major BoNT serotypes for the development of a recombinant protein vaccine. This study is an evaluation of adsorption profiles for three of the recombinant protein antigens to aluminum salt adjuvants in the development of a trivalent vaccine against BoNT. Adsorption profiles were obtained over a range of protein concentrations. The results document that charge-charge interactions dominate the adsorption of antigen to adjuvant. Optimal conditions for adsorption were determined. However, potency studies and solution stability studies indicated the necessity of using aluminum hydroxide adjuvant at low pH. To improve the adsorption profiles to AlOH adjuvant, phosphate ions were introduced into the adsorption buffers. The resulting change in the adjuvant chemistry led to an improvement of adsorption of the BoNT antigens to aluminum hydroxide adjuvant while maintaining potency. Competitive adsorption profiles were also determined, and showed changes in maximum adsorption from mixed solutions compared to adsorption from individual protein solutions. The adsorption profiles for each protein varied due to differences in adsorption mechanism and affinity for the adjuvant surface. These results emphasize the importance of evaluating competitive adsorption in the development of multivalent vaccine products.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Health Sciences Center, Denver, Colorado, USA. cvessely@insmed.com
authors.forename: Christina
authors.initials: C
authors.lastname: Vessely
authors.forename: Tia
authors.initials: T
authors.lastname: Estey
authors.forename: Theodore W
authors.initials: TW
authors.lastname: Randolph
authors.forename: Ian
authors.initials: I
authors.lastname: Henderson
authors.forename: Rajiv
authors.initials: R
authors.lastname: Nayar
authors.forename: John F
authors.initials: JF
authors.lastname: Carpenter
mesh_terms: D000276:Adjuvants, Immunologic; D000327:Adsorption; D000536:Aluminum Hydroxide; D000941:Antigens / Q000276:immunology*; D001905:Botulinum Toxins / Q000276:immunology*; D004563:Electrochemistry; D005079:Excipients; D020100:Hydrogels; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D013058:Mass Spectrometry; D010449:Peptide Mapping; D010710:Phosphates / Q000032:analysis; D011136:Polysorbates; D011506:Proteins / Q000032:analysis; D012394:Rosaniline Dyes; D012996:Solutions; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013395:Sucrose; D013499:Surface Properties; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000941:Antigens; D005079:Excipients; D020100:Hydrogels; D007202:Indicators and Reagents; D010710:Phosphates; D011136:Polysorbates; D011506:Proteins; D012394:Rosaniline Dyes; D012996:Solutions; D014614:Vaccines, Synthetic; D013395:Sucrose; D000536:Aluminum Hydroxide; C048139:Coomassie blue; D001905:Botulinum Toxins