Construction of Influenza A/H1N1 Virosomal Nanobioparticles

Influenza is one of the main respiratory infections of humans, responsible for 300,000–500,000 annual deaths world-wide. Vaccination is one of the best ways to prevent infections including influenza. Influenza virosomes are virus-like particles, which retain the cell binding and membrane fusion properties of the native virus, but lack the ribonucleoprotein (RNP). A virosomal influenza vaccine has recently been commercially available in Europe (Inflexal V®). The virosome is prepared by membrane solubilization and reconstitution. A new method based on dialyzable detergent has been developed to produce virosomes from an A/H3N2 influenza virus. In this study attempt was made to construct a virosomal nanobioparticle of influenza A/ PR8 (H1N1). The Madine-Darby Canine kidney (MDCK) cell line was cultured and infected with influenza virus strain A/PR8 and the culture media were harvested and the virus was purified by ultracentrifugation and concentrated by ultrafiltration. Purified influenza virus was treated with 1, 2-dicaproyl-sn-glycero-3-phosphocholine (DCPC) as a solubilizing detergent to resolve the viral envelope. Ribonucleoprotein was sedimented by ultracentrifugation and the supernatant consisting phospholipids and glycoproteins of influenza virus was reconstituted by removal of DCPC using overnight dialysis against Hank's Buffered Saline (HBS) solution. Finally, the empty influenza virus envelope, called virosome, was observed by transmission electron microscopy (TEM). The size of these particles was estimated to be 50-100 nm. Virosome has been used as a new vaccine formulation and since it is a nontoxic adjuvant carrier it can be used to improve the present commercialized and new vaccines.