Influenza Virosomes as Delivery Systems for Antigens

Infl uenza viruses are the cause of outbreaks of acute respiratory disease, known as infl uenza or ‘ fl u ’ , which have affl icted man and animals since ancient times [1, 2] . Infl uenza viruses are classifi ed in the Orthomyxoviridae family. They are divided into three genera, infl uenza A, B and C viruses, which can be distinguished on the basis of antigenic differences between their nucleoprotein s ( NP s) and matrix ( M ) proteins. Infl uenza A viruses are primarily avian viruses, but also infect a wide variety of animals, including pigs, horses, and seals. Type A viruses are further divided into subtypes based on the antigenic nature of their surface glycoproteins haemagglutinin ( HA ) and neuraminidase ( NA ).