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Vaccine. 2014 Feb 19;32(9):1049-54. doi: 10.1016/j.vaccine.2014.01.012. Epub 2014 Jan 15.

Characterization of the structural modifications accompanying the loss of HBsAg particle immunogenicity.

Author information

1
Laboratoire de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de pharmacie, 74 route du Rhin, 67401 Illkirch, France.
2
Sanofi Pasteur, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Étoile, France.
3
Laboratoire d'Enzymologie et Biochimie Structurales (LEBS) UPR 3082 du CNRS, Campus CNRS, Bâtiment 34, Avenue de la Terrasse, F-91198 Gif-sur-Yvette Cedex, France.
4
Centre de Biochimie Structurale, CNRS UMR 5048-Inserm U1054, Université de Montpellier, 29 rue de Navacelles, 34090 Montpellier Cedex, France.
5
Laboratoire de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de pharmacie, 74 route du Rhin, 67401 Illkirch, France. Electronic address: yves.mely@unistra.fr.

Abstract

The aim of this work was to further understand the relationship between the immunogenicity and the structure of Hepatitis B surface antigen (HBsAg) particles used in Hepatitis B vaccines. To reach this aim, we compared by using a large range of techniques, the structure and properties of untreated particles with those of particles stored for 3 weeks at +60°C, a treatment which resulted in a loss of HBsAg antigenicity (toward RF-1 mAb) and immunogenicity (in mice). While untreated particles imaged by electron microscopy and atomic force microscopy appeared as isolated nanoparticles of ∼ 20nm, heated particles appeared as long chains of particle aggregates with a partial loss of their protein protrusions. Moreover, infrared spectroscopy and circular dichroism revealed that the secondary structure of the S proteins was significantly affected, with a loss of 10% of their α-helix content. Steady-state and time-resolved fluorescence data further revealed strong modifications of the most emitting Trp residues at the particle surface, confirming significant changes in the conformation of the S proteins. Moreover, modifications in the organization of both the lipid core and lipid membrane surface of the heated particles were evidenced by environment-sensitive 3-hydroxyflavone probes. Taken together, our data evidenced a clear relationship between the bona fide S protein structure and lipid organization notably at the particle surface and the particle immunogenicity.

KEYWORDS:

Atomic force microscopy; Electron microscopy; Fluorescence spectroscopy; Fourier transform infrared spectroscopy; Hepatitis B surface antigen; Immunogenicity

PMID:
24440114
DOI:
10.1016/j.vaccine.2014.01.012
[Indexed for MEDLINE]

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