Application of salivary antibody immunoassays for the detection of incident infections with Norwalk virus in a group of volunteers

• Type of Material: Article
• Authors: Shannon M. Griffin, U.S. Environmental Protection Agency; Reagan R. Converse, U.S. Environmental Protection Agency; Juan Leon, Emory University; Timothy J. Wade, U.S. Environmental Protection Agency; Xi Jiang, Cincinnati Children’s Hospital Medical Center; Christine Moe, Emory University; Andrey I. Egorov, U.S. Environmental Protection Agency
• Language: English
• Date: 2015-09-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2015 Elsevier B.V.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.jim.2015.05.001
• Title of Journal or Parent Work: Journal of Immunological Methods
• ISSN: 0022-1759
• Volume: 424
• Start Page: 53
• End Page: 63
• Grant/Funding Information: This work was supported in part (to Juan S. Leon) by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under Award Number K01AI087724.
• Keywords: Salivary antibody; RESPONSES; ANTIGEN; SERUM; Science & Technology; UNITED-STATES; Biochemical Research Methods; ORAL FLUID; Life Sciences & Biomedicine; GASTROENTERITIS OUTBREAKS; Incident infection; Volunteer challenge study; Immunology; NOROVIRUS OUTBREAKS; DIVERSITY; Immunoassay; GENOGROUP; DRINKING-WATER; Biochemistry & Molecular Biology; Norovirus
• Research Categories: Health Sciences, Immunology; Health Sciences, Pathology; Health Sciences, Public Health

Abstract

Norovirus infection is the most common cause of acute gastroenteritis in developed countries. Developing an assay based on a non-invasive biomarker for detecting incident norovirus infections could improve disease surveillance and epidemiological investigations. This project involved analysis of IgA and IgG norovirus-specific antibody responses in saliva samples from a Norwalk virus (Genogroup I, genotype 1 norovirus) challenge study involving infected and symptomatic, and non-infected asymptomatic individuals. Saliva was collected at the challenge, and two weeks and 40. days post-challenge. Samples were analyzed using the Luminex fluorometric and Meso Scale Discovery (MSD) electrochemiluminescence immunoassays. Recombinant P domains of Norwalk virus capsid protein, as well as similar recombinant proteins of two genogroup II noroviruses (VA387 and VA207) were used as antigens. Immunoconversions were defined as >. 4-fold increase in antibody responses to the norovirus antigens. Various sample pre-treatment options, buffers, saliva dilution ratios, and data adjustment approaches to control for sample-to-sample variability in saliva composition were compared using the Luminex assay. The results suggest that adjusting responses to the norovirus antigens for responses to the protein purification tag, glutathione-S-transferase (GST), significantly improved the odds of producing a correct immunoconversion test result. IgG-based tests were more accurate compared to IgA-based tests. At optimal conditions, both Luminex and MSD assays for Norwalk-specific IgG antibodies correctly identified all infected and non-infected individuals. There was no evidence of cross-reactivity of anti-Norwalk virus antibodies with genogroup II noroviruses. These results suggest that salivary antibody responses can be used for the detection of incident infections with Norwalk virus in prospective surveys.