Establishment Of Reverse Genetics System Of A/Sichuan/01/2009 Pandemic A/H1N1

Influenza A virus exists in amlost all of homothermal anmials and is the prime type leading to infection in humans and anmials.Under natura lcircum stances,influenza virus has certa in host range.In general, influenza virus of human origin cannot replicate in birds,such as chickens or ducks.Likewise, avian influenza virus has very low replication ability in prmiates.In the past several years ,however, there have been many incidents that avian in fluenza virus (including H5N1, H9N2 and H7N7 subtypes) have transmitted from avian to human. Studies have demonstrated that the differences in viral molecular structure and the interaction between virus and host cell determine influenza virus pathogenicity and interspecies transmission and the molecular biology basis for such changes are mutations of certa in amino acids in functional sites on structural or nonstructural proteins.In early April 2009, a new influenza pandemic emerged in Mexico and the United States. The surveillance results show that the virus spread worldwide to 30 countries by human-to-human transmission during the first few weeks. For which the World Health Organization (WHO) raise its pandemic alert to level 6/6. After isolation and identification of the pathogen, WHO announced that the first influenza pandemic in this 21st century caused by a novel swine-origin influenza virus A H1N1. The origin of the new influenza virus is very complex. It is a multiple reassortment virus. The hemagglutinin (HA) gene was derived from the 1918 swine influenza virus, other genes from human, avian and Europe swine influenza viruses. Although there were many incidents of human infected with swine influenza, but the scope was very limited. Now, people focus on how this swine influenza virus can break the species barrier and transmit efficiently between human.To understand the transmission of this pandemic, we choose the Pandemic H1N1 Influenza virus A/Sichuan/01/2009(SC/01) as parent virus. Eight plasmids containing SC/01 genome were constructed to rescue SC/01.The rescued virus is named as Rescue-A/Sichuan/01/2009(R-SC/01). The whole genome sequence showed that there was no nucleic acid change in R-SC/01, compared with SC/01. Furthermore, these two viruses showed identical 50% mouse infectious dose (MID50) and receptor binding ability. Our results could provide a technique for further study of SC/01, especially the crossing-host-barrier transmission mechanisms.