Our activities on influenza viruses (IVs), SARS coronavirus (SARS-CoV), hepatitis C virus (HCV) and GB virus B (GBV-B), include studies of the molecular evolution, expression and replication of the viral genomes, analysis of virus host interactions and evaluation of vaccines and antiviral candidates.

Evolution of influenza viruses

As a National Influenza Center (Northern France) and WHO Collaborating Center, our activities involve the surveillance of human IVs. In collaboration with the Institut Pasteur in Cambodia, new H5N1 IVs from human and avian origin were analyzed. Avian IVs of various subtypes (but no highly pathogenic H5N1 viruses) were further detected in waterbirds from the Camargue and Dombes areas (coll M. Gauthier-Clerc, Tour du Valat, F. Renaud, IRD/CNRS Montpellier; M. Artois, ENV Lyon).

Signals at the extremities of genomic IV segments

Signals within the non-coding regions of the viral segments were further compared for type A and C viruses using a transient transcription/replication assay as well as in the context of infectious viruses. To this end, a reverse genetics system previously not described for type C viruses was developed.

Host range determinants of the IV polymerase Functional characteristics of polymerase complexes derived from human and avian IVs have previously been related to interactions with PB2 residue 627. The functional significance of candidate interacting host factors identified by the use of an IV expressing a tagged PB2 or by yeast double-hybrid (coll Y. Jacob, PO. Vidalain, IP) is being analyzed.

SARS-CoV vaccine candidates

Potent adjuvants were found to enhance the immunogenicity and level of protection conferred by a soluble form (Ssol) of the spike protein of SARS-CoV in mice or hamsters. Furthermore, recombinant viral vectors expressing the spike protein of SARS-CoV were found to induce protective immune responses (coll. P. Marianneau, UBIVE, Lyon, P. Charneau - M. Huerre – F. Tangy, IP Paris).

Hepacivirus (HCV, GBV-B) replication

Using both HCV and the closely-related, primate hepatotropic virus GBV-B, in cell culture systems or in vivo, we mapped molecular determinants of genome replication, and investigated the functions and specificities of encoded ion channel proteins and NS3/4A proteases towards a therapeutical aim. We also generated a chimeric GBV-B which polyprotein translation depends on HCV sequences (coll. S.M. Lemon, R.E. Lanford, USA). This virus may be used in the primate model to validate antiviral candidates targeting these HCV sequences, such as siRNAs that we identified as efficient inhibitors of HCV infection in cell culture (coll. F. Colbère-Garapin, IP ; C. Wychowski, Lille).

Keywords: Influenza, respiratory viruses, vaccine, polymerase, host factors, evolution hepatitis, replication, hepacivirus, antiviral

Callendret B., V. Lorin, P. Charneau, P. Marianneau, H. Contamin, J-M. Betton, S. van der Werf and N. Escriou. (2007) Heterologous viral RNA export elements improve expression of severe acute respiratory syndrome (SARS) coronavirus spike protein and protective efficacy of DNA vaccines against SARS. Virology 5;363(2):288-302.

Crescenzo-Chaigne B. and van der Werf S. (2007) Rescue of influenza C virus from recombinant DNA J. Virol 81(20):11282-9

C. Chevalier, A. Saulnier, Y. Benureau, D. Fléchet, D. Delgrange, F. Colbère-Garapin, C. Wychowski, and A. Martin (2007). Identification of siRNAs that efficiently inhibit hepatitis C virus replication in cell culture. Mol. Therapy, 15, 1452-1462.

Rameix-Welti MA, Agou F, Buchy P, Mardy S, Aubin JT, Veron M, van der Werf S and Naffakh N. (2006) Natural variation can significantly alter the sensitivity of influenza A (H5N1) viruses to oseltamivir. Antimicrob Agents Chemother.50(11):3809-15.

Dos Santos Afonso, E., Escriou, N., Leclercq, I., van der Werf, S., and Naffakh, N. (2005). The generation of recombinant influenza A viruses expressing a PB2 fusion protein requires the conservation of a packaging signal overlapping the coding and noncoding regions at the 5' end of the PB2 segment.Virology 341 (1):34-46.