Hepatitis E Virus Lifecycle and Identification of 3 Forms of the ORF2 Capsid Protein

Cycle infectieux du virus de l'hépatite E et identification de 3 formes de la protéine de capside ORF2

Claire Montpellier (1) , Czeslaw Wychowski (1) , Ibrahim M Sayed (2, 3) , Jean-Christophe Meunier (4) , Jean-Michel Saliou , Maliki Ankavay (1) , Anne Bull (4) , André Pillez (1) , Florence Abravanel , François Helle (5, 6) , Etienne Brochot (5, 7, 6) , Hervé Drobecq (8) , Rayan Farhat (1) , Cécile-Marie Aliouat-Denis (1) , Juliano G Haddad (1) , Jacques Izopet (9) , Philip Meuleman (2) , Anne Goffard (1) , Jean Dubuisson (1) , Laurence Cocquerel (1)

1 CIIL - Centre d’Infection et d’Immunité de Lille - INSERM U 1019 - UMR 9017 - UMR 8204
2 UGENT - Universiteit Gent = Ghent University
3 Assiut University
4 MAVIVHe - Morphogénèse et antigénicité du VIH, des Virus des Hépatites et Emergents
5 UVCF - Unité de Virologie clinique et fondamentale
6 AGIR - Agents infectieux, résistance et chimiothérapie - UR UPJV 4294
7 Laboratoire de Virologie [CHU Amiens]
8 M3T - Mécanismes de la Tumorigénèse et Thérapies Ciblées - UMR 8161
9 Laboratoire Virologie [CHU Toulouse]

BACKGROUND & AIMS: Hepatitis E virus (HEV) infection is a major cause of acute hepatitis worldwide. Approximately 2 billion people live in areas endemic for HEV and are at risk of infection. The HEV genome encodes 3 proteins, including the ORF2 capsid protein. Detailed analyses of the HEV life cycle has been hampered by the lack of an efficient viral culture system. METHODS: We performed studies with gt3 HEV cell culture-produced particles and patient blood and stool samples. Samples were fractionated on iodixanol gradients and cushions. Infectivity assays were performed in vitro and in human liver chimeric mice. Proteins were analyzed by biochemical and proteomic approaches. Infectious particles were analyzed by transmission electron microscopy. HEV antigen levels were measured with the Wantaï enzyme-linked immunosorbent assay. RESULTS: We developed an efficient cell culture system and isolated HEV particles that were infectious in vitro and in vivo. Using transmission electron microscopy, we defined the ultrastructure of HEV cell culture-produced particles and particles from patient sera and stool samples. We also identified the precise sequence of the infectious particle-associated ORF2 capsid protein. In cultured cells and in samples from patients, HEV produced 3 forms of the ORF2 capsid protein: infectious/intracellular ORF2 (ORF2i), glycosylated ORF2 (ORF2g), and cleaved ORF2 (ORF2c). The ORF2i protein associated with infectious particles, whereas the ORF2g and ORF2c proteins were massively secreted glycoproteins not associated with infectious particles. ORF2g and ORF2c were the most abundant antigens detected in sera from patients. CONCLUSIONS: We developed a cell culture system and characterized HEV particles; we identified 3 ORF2 capsid proteins (ORF2i, ORF2g, and ORFc). These findings will advance our understanding of the HEV life cycle and improve diagnosis.

Mots clés: Hepatitis E; Infectious Particles; ORF2 Products; PLC/PRF/5 Cells

Domaines: Virologie

Claire Montpellier, Czeslaw Wychowski, Ibrahim M Sayed, Jean-Christophe Meunier, Jean-Michel Saliou, et al.. Hepatitis E Virus Lifecycle and Identification of 3 Forms of the ORF2 Capsid Protein. Gastroenterology, 2018, 154 (1), pp.211-223.e8. ⟨10.1053/j.gastro.2017.09.020⟩. ⟨hal-02117643⟩