Isabelle Legastelois received her Ph.D. degree from Lyon I university, France. She joined Sanofi Pasteur in June 1999. Dr. Legastelois is presently a Research unit head in the Research and Non Clinical Safety department of Sanofi Pasteur, France. Her main activities are the development and improvement of influenza and rabies vaccines, assessment of different expression systems for the production of viral antigens and development of new techniques to quantify viral antigens. Prior to her present position she worked in public-sector laboratories on HIV and visna-maedi lentiviruses


The membrane displayed antigen haemagglutinin (HA) from several influenza strains were expressed in the Leishmania tarentolae system. This non-conventional expression system based on a parasite of lizards, can be readily propagated to high cell density (>108 cells/ml) in a simple incubator at 26°C. The genes encoding HA proteins were cloned from six influenza strains, among these being a 2009 A/H1N1 pandemic strain from swine origin, namely A/California/07/09(H1N1). Soluble HA proteins were secreted into the cell culture medium and were easily and successfully purified via a His-Tag domain fused to the proteins. The overall process could be conducted in less than 3 months and resulted in a yield of approximately 1.5 to 5 mg of HA per liter of biofermenter culture after purification. The recombinant HA proteins expressed by L. tarentolae were characterized by dynamic light scattering and were observed to be mostly monomeric. The L. tarentolae recombinant HA proteins were immunogenic in mice at a dose of 10µg when administered twice with an oil-in-water emulsion-based adjuvant. These results suggest that the L. tarentolae expression system may be an alternative to the current egg-based vaccine production

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