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@#Objective To analyze the evolutionary characteristics of GZ19 strain of G Ⅱ.4 norovirus(NoV) in China,and clarify its ability and mode of binding to receptors of histo-blood group antigens(HBGAs).Methods According to the sequence of ORF2 region in GZ19 strain,the evolutionary tree was constructed and the amino acid sequences at HBGA binding sites(HBSs) and key blocking epitopes were analyzed.P particles were expressed by prokaryotic expression system and purified.The obtained protein was identified by SDS-PAGE and indirect ELISA,and analyzed for the receptor binding characteristics of P particles by saliva binding and oligosaccharide binding assays.Results The GZ19 strain belonged to G Ⅱ.4Sydney [P31] lineage,of which the amino acid sequences of receptor binding sites and blocking epitopes were relatively conservative.It showed high homology with other G Ⅱ.4 Sydney [P31] strains in recent five years,while significant difference from G Ⅱ.4 Sydney 2012 original strain and G Ⅱ.4 Sydney [P16] strains.P particles only combined with A,B,O,AB secretory saliva and H-di oligosaccharide.Conclusion GZ19 strain represented the current evolutionary direction of G Ⅱ.4Sydney [P31] NoV.The successful expression of P particles and analysis of the binding characteristics with HBGA receptors laid a foundation of the research of epidemic evolution dynamics and vaccine development of G Ⅱ.4 NoVs in China.
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Pediatric gastroenteritis is a major cause of childhood mortality and morbidity worldwide, especially in developing countries. Diarrhoea can be caused by a variety of different pathogens including bacteria, viruses and parasites. Among the viruses; Rotavirus has been extensively studied and is responsible for 44% of GE cases. As the Rotavirus vaccination coverage improves, the causative agent’s shift may be more towards the Calciviruses (Norovirus, Sappovirus) and other similar viruses, and consequently the investigations should focus on these viruses in future. This study was conducted in a Teaching hospital, Hyderabad, Telangana State included 118 cases of Gastroenteritis of which 6 cases were positive for Norovirus (NoV) i.e.; 5% of cases were NoV positive by RIDASCREEN EIA and RIDA QUICK, the rapid test for NoV virus. These 6 cases were children between 7 months and one and half year old. The age profile showed a fall in the number of diarrhoea cases as the child’s age increases. 63 (53.3%) were male children and 55 (46.6%) were female children. In children < 2 years (n=83), 22 (26.5%) were breast fed, 30 (36.1%) were bottle fed and 7 (8.4%) were on mixed Alimelu M, Radha Mohan M., Vindhya Tuladi, Sudhershan Reddy P, Shailaja V.V., Preeti Nagaraj G. Prevalence of Norovirus and epidemiology of acute gastroenteritis in children. IAIM, 2016; 3(6): 157-163. Page 158 feeds. Among mothers 25.42% never washed their hands with soap, 60.16% used soap occasionally and only 14.4% always used soap. 43.2 % presented with no dehydration, 27.96% presented with some dehydration and 28.8% presented with severe dehydration. 70.3% of mothers continued to feed during diarrhoea. Regarding the treatment used for diarrhoea before admission in hospital, 42.37% used ORS, 27.11% used both ORS and antibiotics, 55.08% were on antibiotics and 11% took no treatment at all.
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Objective To evaluate the immune effects of virus-like particles ( VLPs) of VP1 pro-teins derived from norovirus GⅠ. 1 and GⅡ. 4 genotypes expressed in Hansenula polymorpha expression sys-tem. Methods SDS-PAGE and Western blot assay were performed to detect the purity of GⅠ. 1 and GⅡ. 4 VP1 proteins after purification. Morphologies of the recombinant VLPs were observed under transmission electron microscopy ( TEM) . Sizes and distributions of the VLPs were analyzed by dynamic light scattering analyzer. BT50(50% of blocking titer) was detected by HBGA (histo-blood group antigen) blocking assay in BALB/c mice immunized with different regimens. Results SDS-PAGE analysis of the purified recombinant GⅠ. 1 and GⅡ. 4 VP1 proteins showed that their purity were greater than 90%. Western blot assay con-firmed the specific bands of VLPs. TEM images showed that the sizes of purified GⅠ. 1 and GⅡ. 4 VP1 VLPs were at a mean diameter of 30-50 nm with clear border and high homogeneity, which was similar to that of wild virus. BT50 significantly increased in the groups, in which Al( OH) 3 was used as adjuvant. Con-clusion Animal studies have shown that administration of GⅠ. 1 and GⅡ. 4 VP1 VLPs in the presence of Al( OH) 3 induces detectable HBGA-blocking antibody, indicating that GⅠ. 1 and GⅡ. 4 VP1 VLPs are promising candidates for norovirus vaccine.