Anti-Norovirus Capsid protein VP1 Polyclonal antibody

Noroviruses are a very diverse group of viruses that infect different mammalian species. In humans, norovirus is a major cause of acute gastroenteritis. Multiple norovirus infections can occur in a lifetime as the result of limited duration of acquired immunity and cross-protection among different strains. A combination of advances in sequencing methods and improvements on surveillance has provided new insights into norovirus diversification and emergence. The generation of diverse norovirus strains has been associated with (1) point mutations on two different genes: ORF1, encoding the nonstructural proteins, and ORF2, encoding the major capsid protein (VP1); and (2) recombination events that create chimeric viruses. While both mechanisms are exploited by all norovirus strains, individual genotypes utilize each mechanism differently to emerge and persist in the human population. GII.4 noroviruses (the most prevalent genotype in humans) present an accumulation of amino acid mutations on VP1 resulting in the chronological emergence of new variants. In contrast, non-GII.4 noroviruses present co-circulation of different variants over long periods with limited changes on their VP1. Notably, genetic diversity of non-GII.4 noroviruses is mostly related to the high number of recombinant strains detected in humans. While it is difficult to determine the precise mechanism of emergence of epidemic noroviruses, observations point to multiple factors that include host-virus interactions and changes on two regions of the genome (ORF1 and ORF2). Larger datasets of viral genomes are needed to facilitate comparison of epidemic strains and those circulating at low levels in the population. This will provide a better understanding of the mechanism of norovirus emergence and persistence.

In this study, the genome sequence of a norovirus GII.4 strain isolated from South China was comparatively analyzed. The RNA genome of the strain GZ2013-L10 was composed of 7513 nucleotides. Phylogenetic analyses based on three ORFs confirmed its genotype as GII.Pe/GII.4-2012. Compared with other 22 genomes of the same variant, nine distinct nucleotide substitutions were found in the new genome, which resulted in three amino acid changes. All 138 capsid protein VP1 sequences of GII.4-2012 variants were also collected, and multiple alignments revealed 35 variable codons. Evolutionary analyses of GII.4-2012 variants were performed against previous pandemic GII.4 variants, and 2 distinctive changes were identified on epitopes A and E (E368, T413), which resulted in an obvious variation of their solvent-accessible surface areas. Therefore, the genome of GZ2013-L10 was extensively characterized, and new emerging variations on viral epitopes were predicted to contribute to NoV persistence in humans.