title: Serological studies confirm the novel astrovirus HMOAstV-C as a highly prevalent human infectious agent.
abstract: Molecular identification of a microbe is the first step in determining its prevalence of infection and pathogenic potential. Detection of specific adaptive immune responses can provide insights into whether a microbe is a human infectious agent and its epidemiology. Here we characterized human anti-IgG antibody responses by luciferase immunoprecipitation systems (LIPS) against two protein fragments derived from the capsid protein of the novel HMOAstV-C astrovirus. While antibodies to the N-terminal fragment were not informative, the C-terminal capsid fragment of HMOAstV-C showed a high frequency of immunoreactivity with serum from healthy blood donors. In contrast, a similar C-terminal capsid fragment from the related HMOAstV-A astrovirus failed to show immunoreactivity. Detailed analysis of adult serum from the United Sates using a standardized threshold demonstrated HMOAstV-C seropositivity in approximately 65% of the samples. Evaluation of serum samples from different pediatric age groups revealed that the prevalence of antibodies in 6-12 month, 1-2 year, 2-5 year and 5-10 year olds was 20%, 23%, 32% and 36%, respectively, indicating rising seroprevalence with age. Additionally, 50% (11/22) of the 0-6 month old children showed anti-HMOAstV-C antibody responses, likely reflecting maternal antibodies. Together these results document human humoral responses to HMOAstV-C and validate LIPS as a facile and effective approach for identifying humoral responses to novel infectious agents.
authors.affiliation: Neurobiology and Pain Therapeutics Section, Laboratory of Sensory Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America. burbelop@nidcr.nih.gov
authors.forename: Peter D
authors.initials: PD
authors.lastname: Burbelo
authors.forename: Kathryn H
authors.initials: KH
authors.lastname: Ching
authors.forename: Frank
authors.initials: F
authors.lastname: Esper
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Iadarola
authors.forename: Eric
authors.initials: E
authors.lastname: Delwart
authors.forename: W Ian
authors.initials: WI
authors.lastname: Lipkin
authors.forename: Amit
authors.initials: A
authors.lastname: Kapoor
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000096:biosynthesis; D019350:Astroviridae Infections / Q000453:epidemiology* / Q000821:virology; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D017931:DNA Primers; D006801:Humans; D007223:Infant; D001257:Mamastrovirus / Q000276:immunology / Q000472:pathogenicity*; D016133:Polymerase Chain Reaction; D016036:Seroepidemiologic Studies
chemical_list: D000914:Antibodies, Viral; D017931:DNA Primers