The Biological Characteristics Research Of Clinical Isolates Of Human Respiratory Syncytial Virus

Respiratory syncytial virus (RSV) is an important pathogen causing acute lower respiratory infections in infants and young children. Besides, it probably leads to diseases and death of young children, elderly people and patients with low immunity to disease. A vaccination is the most effective way to prevent the RSV, but there still has not any safe and effective RSV vaccines available. So it is vital to do some research on RSV-related knowledge, like its fashion trends, separation and purification, its cultural characteristics and so on, which would provide an important sample for the development of RSV vaccine.There are three major themes in the experiment of this paper:(1) detection of virus from clinical samples cultures in vero cells; (2) identification and classification of RSV; (3) characteristics of RSV isolates.(1) Detection of virus from clinical samples cultures in vero cellsIn this study, we chose 11 sampels from 48 children sputum, which could result in a syncytial phenomenon for vero cells, and detected the type of those isolates’ syncytial respiratory virus. The analysis shows that there are 5 RSV,7 MuV,4 PIV2 viruses,2 PIV3 viruses, and 10 AdV in the 11 cultures, while MeV, PIV1 and RV viruses are not found. We also find that it is single RSV infection in the culture containing the isolates QY-33, but it is mixed infection in others, that is, there are two or more viruses that made a syncytial phenomenon for vero cells.(2) Identification and classification of RSVThe isolates QY-33, which is the only one single RSV infection was identified, sequenced and compared right. We find that it is the RSV virus. Then we amplified its G protein gene by nested PCR, sequenced alignment, and analyzed phylogenetic. Finally, the data shows that the isolates of RSV is GA1 subtypes.(3) Characteristics of RSV isolatesWe explored the relevant biological culture characteristics of RSV isolates QY-33. Replication of RSV in different cells shows that A549 cells are the most sensitive to RSV; Replication of RSV in the culture process and the cell culture supernatant show that most RSV are located in the culture supernatant when the cell lesions are more than 90%; Replication of RSV in different temperature indicates that RSV optimal culture temperature is 37℃,and 32℃ is also OK; We also attempt to use microcarriers techniques to culture vero cells and produce RSV virus, and the result shows that the outcome is pretty ideal.In conclusion, the study obtained a RSV isolates strain QY-33 from children’s screening sputum samples, and analyzed its type, growth culture characteristics. We also developed a modern bioreactor-microcarrier culture technique. To be specific, we use it to culture Vero cells and produce RSV virus. It would lay a foundation for large-scale cultivation of the virus and the development of RSV vaccine.