Anti-Norovirus Capsid protein VP1 Polyclonal antibody

Norovirus is a highly transmissible infectious agent that causes epidemic gastroenteritis in susceptible children and adults. Norovirus infections can be severe and can be initiated from an exceptionally small number of viral particles. Detailed genome sequence data are useful for tracking norovirus transmission and evolution. To address this need, we have developed a whole-genome deep-sequencing method that generates entire genome sequences from small amounts of clinical specimens. This novel approach employs an algorithm for reverse transcription and PCR amplification primer design using all of the publically available norovirus sequence data. Deep sequencing and de novo assembly were used to generate norovirus genomes from a large set of diarrheal patients attending three hospitals in Ho Chi Minh City, Vietnam, over a 2.5-year period. Positive-selection analysis and direct examination of protein changes in the virus over time identified codons in the regions encoding proteins VP1, p48 (NS1-2), and p22 (NS4) under positive selection and expands the known targets of norovirus evolutionary pressure. IMPORTANCE The high transmissibility and rapid evolutionary rate of norovirus, combined with a short-lived host immune responses, are thought to be the reasons why the virus causes the majority of pediatric viral diarrhea cases. The evolutionary patterns of this RNA virus have been described in detail for only a portion of the virus genome and never for a virus from a detailed urban tropical setting. We provide a detailed sequence description of the noroviruses circulating in three Ho Chi Minh City hospitals over a 2.5-year period. This study identified patterns of virus change in known sites of host immune response and identified three additional regions of the virus genome under selection that were not previously recognized. In addition, the method described here provides a robust full-genome sequencing platform for community-based virus surveillance.

GII.3 and GII.6 noroviruses (NoVs) are similar in several aspects, including the presence of a short sequence insertion in the P2 domain of the major capsid protein (VP1) and trypsin susceptibility of VP1-containing virus-like particles (VLPs). In this study, we generated two constructs with the S or P domains of VP1 from GII.3 and GII.6 NoV strains exchanged (GII.3S/GII.6P and GII.6S/GII.3P), and the resultant chimeric capsid proteins were expressed from recombinant baculoviruses. The assembly of VLPs was confirmed by electron microscopy, and the susceptibility of assembled VLPs to trypsin digestion was analyzed by SDS-PAGE. Salivary histo-blood group antigen (HBGA) binding and binding blockade assays were performed to determine the binding characteristics of chimeric VP1-containing VLPs with and without trypsin digestion. Our results indicated that both expressed GII.3S/GII.6P and GII.6S/GII.3P chimeric proteins successfully assembled into VLPs. Trypsin digestion of VLPs assembled from both chimeric proteins led to the generation of two fragments with molecular sizes similar to those of wild-type VP1-containing VLPs. An in vitro salivary HBGA binding assay demonstrated that VLPs assembled from both chimeric proteins exhibited enhanced binding after trypsin cleavage. An HBGA binding blockade assay indicated that the binding of GII.3S/GII.6P and GII.6S/GII.3P VLPs against salivary HBGAs could only be blocked by GII.3 and GII.6 NoV VLP-specific hyperimmune sera, respectively. For GII.6 and GII.3S/GII.6P VLPs, a difference in binding enhancement after trypsin cleavage was observed. Our results demonstrate that the S domains of GII.3 and GII.6 NoV VP1 are interchangeable and that the S domain affects the binding of the P domain to HBGAs.