Group A Rotavirus Of Vp5 ~ * And Vp8 To ~ * Expression And Immunological Properties

Rotaviruses (RVs), as a member of the Reoviridae family, has a triple-layered capsid without envelope, approximately 70 nm in diameter. RV was recognized in 1973 as the primary aetiological agent leading to nonbacterial childhood gastroenteritis, estimated to be responsible for approximately 600,000 deaths due to acute gastrointestinal diseases in young children throughout the world each year. RV genome comprises 11 segments of double-stranded RNA, which encodes 6 structural proteins and 6 non-structural proteins. According to the antigenic specificity of the VP6 protein, which constitutes the internal capsid, the RV strains are classified into 7 groups (A to G), and in which group A RVs are the major cause of acute gastroenteritis in infants and young children.Usually, the VP4 of group A RV which forms spike-like projections lies in the outer coats and anchored to the intermediate layer of the VP6 protein. VP4 protein is the major cross neutraliziong antigen of the virus, and has an esscential role during the early interactions of the virus with the cell surface, including receptor binding and cell penetration. Cleavage of the VP4 protein prior to cell attachment by trypsin-like enzymes into two peptide fragments VP5* and VP8* in the gut that associated with the virus particle, enhancing its infectivity. In order to further investigate properties of these two proteins, open reading frame (ORF) sequences of VP5* and VP8* proteins derived from the VP4 of RV strain TB-Chen were cloned and expressed, and their immunological characteristics were analyzed. The resuLts showed that VP5* and VP8* proteins couLd be highly expressed in E. coli cells, possessing 32% and 41% of the total cell proteins, respectively; the expressed recombinant VP5* (rVP5*) and VP8* (rVP8*) couLd elicit specific antibodies in guinea pigs, these antibodies couLd recognize the recombinant VP4 derived from TB-Chen strain and the VP4 protein synthesized in Wa infected or SA11 infected MA104 cells. The resuLts indicated that rVP5* and rVP8* have good immunogenicity and anti-rVP5* and anti-rVP8* antibodies have high specificity and cross reactivity.These resuLts lay the foundation for further study on the structure and function, immunological properties and practical use of the VP5* and VP8*.