Serotype-specific antigen ELISA for detection of Chiba virus in stools

Abstract

Chiba virus (CV), a Norwalk-like virus (NLV), was first identified as a cause of oyster-associated outbreak of gastroenteritis that occurred in Chiba prefecture, Japan, in 1987. An enzyme-linked immunosorbent assay (ELISA), based on hyperimmune antisera to recombinant baculovirus-expressed capsid proteins of CV (rCV), was developed to detect CV antigen in stools. No cross-reactions were observed with other enteric viruses including enteroviruses, rotaviruses, astroviruses, or enteric adenoviruses. The ELISA was used to screen 101 stools collected from 16 oyster-associated outbreaks of acute gastroenteritis. Twelve stools (11.9%) from seven outbreaks were positive for CV antigen. Ten rCV ELISA-positive strains were confirmed by RT-PCR and nucleotide sequencing. ELISA-positive strains showed 96-100% nucleotide sequence identity to each other, though they were obtained nine years apart. Phylogenetic analysis demonstrated that all ten strains clustered with the prototype CV in genogroup I viruses. We concluded that the antigen ELISA described in this study is highly type-specific, and that this method should be useful for epidemiological surveys of Chiba virus infections.

Cross-Reactivity among Several Recombinant Calicivirus Virus-Like Particles (VLPs) with Monoclonal Antibodies Obtained from Mice Immunized Orally with One Type of VLP

“…The rNV, rSMA, rGV, and rSV VLPs were produced in the Division of Molecular Virology, Baylor College of Medicine. The recombinant rCV, rUEV, rSeV, rCHV, rFUV, rKAV, and rNAV VLPs were produced in the Department of Virology II, National Institute of Infectious Diseases (29)(30)(31)43; N. Takeda, unpublished data). Protein concentrations were determined using the Bio-Rad protein assay kit (BioRad Laboratories, Hercules, Calif.), with bovine serum albumin as the protein standard.…”

Evaluation and Comparison of Two Commercial Enzyme-Linked Immunosorbent Assay Kits for Detection of Antigenically Diverse Human Noroviruses in Stool Samples

“…Comparison of the reactivities with VLPs of antibodies raised in animals by immunization of VLPs from different genetic groups has consistently suggested that GI and GII correspond to two distinct major antigenic types and that the genetic subgroups within GI and GII each correspond to distinct antigenic subtypes. While the rabbit anti-VLP polyclonal antibodies obtained in those studies were predominantly specific for the genetic subgroups of HuNVs used as the immunogen (11,18,24,25), mouse MAbs recognizing epitopes common to either GI or GII, or both GI and GII, have also been reported (12,14,22,42). These MAbs, which have the ability to react with a wide range of antigenically diverse HuNVs, could be useful for the development of a simple and rapid ELISA method for the detection of virus in stool samples.…”

“…A prerequisite for such cross-reactivity is the use of both capture and detector antibodies with the capability to recognize epitopes common to GI and GII HuNVs. However, the rabbit anti-VLP antibodies produced in many laboratories were generally specific for genetic subgroups (11,18,24,25), and the GI wells of the Denka kit were coated with MAb NV3912, reportedly specific only for VLPs of GI antigens. The authors of the papers evaluating the Denka kit did not provide information on how frequently this cross-reactivity occurred and did not discuss those results.…”

Virological, Serological, and Clinical Features of an Outbreak of Acute Gastroenteritis Due to Recombinant Genogroup II Norovirus in an Infant Home

“…VLPs expressing capsid protein of Sh-5 (NV/GII), Ueno7k (NV/GII), or Chiba (NV/GI) virus were used as NV/GII or NV/GI antigens. The expression and purification of NV VLPs were performed as previously described (23,24,38). Serum samples were tested by ELISA using VLPs as previously described (26).…”