title: Immunogenicity of Structurally Perturbed Hen Egg Lysozyme Adsorbed to Silicone Oil Microdroplets in Wild-Type and Transgenic Mouse Models.
abstract: Silicone oil microdroplets may act as adjuvants, promoting unwanted immune responses against both foreign and self-proteins. Proteins often unfold upon adsorption to silicone oil microdroplets, but it is unclear how such unfolding might affect the immune response. In this study, we found that hen egg lysozyme (HEL) readily adsorbed to silicone oil microdroplets and perturbed the conformation of HEL. We compared the immune response to injections of HEL formulated in the presence and absence of silicone oil microdroplets in both wild-type mice and transgenic littermates that express a soluble form of HEL (sHEL), thus rendering them immunologically tolerant to this nominal self-antigen. Following 2 subcutaneous injections of a HEL formulation containing silicone oil microdroplets, wild-type mice exhibited a stronger IgG1 antibody response against HEL compared to the response in wild-type mice that administered an oil-free HEL formulation. However, when HEL was subcutaneously administered to sHEL-transgenic mice, immunological tolerance to sHEL was not broken in the presence of silicone oil microdroplets. Thus, although structural perturbations in proteins adsorbed to silicone oil microdroplets may augment the immune response, in the case of endogenously expressed proteins, such structural perturbations may not be sufficient to result in a breach of immunological tolerance.
authors.affiliation: Department of Chemical and Biological Engineering, Center for Pharmaceutical Biotechnology, University of Colorado Boulder, Boulder, Colorado 80309.
authors.forename: Carly F
authors.initials: CF
authors.lastname: Chisholm
authors.affiliation: Department of Chemical and Biological Engineering, Center for Pharmaceutical Biotechnology, University of Colorado Boulder, Boulder, Colorado 80309.
authors.forename: Kaitlin R
authors.initials: KR
authors.lastname: Soucie
authors.affiliation: Department of Chemical and Biological Engineering, Center for Pharmaceutical Biotechnology, University of Colorado Boulder, Boulder, Colorado 80309.
authors.forename: Jane S
authors.initials: JS
authors.lastname: Song
authors.affiliation: Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80045.
authors.forename: Pamela
authors.initials: P
authors.lastname: Strauch
authors.affiliation: Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80045.
authors.forename: Raul M
authors.initials: RM
authors.lastname: Torres
authors.affiliation: Department of Pharmaceutical Sciences, Center for Pharmaceutical Biotechnology, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045.
authors.forename: John F
authors.initials: JF
authors.lastname: Carpenter
authors.affiliation: Office of Biological Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland 20993.
authors.forename: Jack A
authors.initials: JA
authors.lastname: Ragheb
authors.affiliation: Department of Chemical and Biological Engineering, Center for Pharmaceutical Biotechnology, University of Colorado Boulder, Boulder, Colorado 80309. Electronic address: Theodore.randolph@colorado.edu.
authors.forename: Theodore W
authors.initials: TW
authors.lastname: Randolph
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D000327:Adsorption; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D002645:Chickens; D005260:Female; D007108:Immune Tolerance; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009113:Muramidase / Q000008:administration & dosage / Q000737:chemistry* / Q000276:immunology*; D066329:Protein Aggregates; D011487:Protein Conformation; D012827:Silicone Oils / Q000008:administration & dosage / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D000276:Adjuvants, Immunologic; D007074:Immunoglobulin G; D066329:Protein Aggregates; D012827:Silicone Oils; C421864:hen egg lysozyme; D009113:Muramidase
keywords: adjuvant effect; immune response; immunogenicity; particle size; prefilled syringes; protein aggregation; protein formulation; protein structure; silicone oil; subvisible particles