title: Development and maturation of norovirus antibodies in childhood.
abstract: The burden of norovirus (NoV) gastroenteritis is substantial in young children. Maternal antibodies are thought to protect a child from NoV infection in early infancy but subsequent development of NoV-specific protective immunity in children is still largely unexplored. We have determined NoV-specific antibody seroconversion to GII.4 virus-like particles as an indicator of NoV infection in two children prospectively followed from birth to eight years of age. Blocking activity and affinity maturation of maternal and serum IgG antibodies were evaluated. Our results show that multiple infections occur in children up to eight years of age. The titer, blocking activity and avidity of maternal antibodies determined susceptibility of an infant to NoV infection. NoV GII.4-specific antibodies with high blocking potential and avidity were developed at two to three years of age and were retained throughout the follow-up. Subsequent NoV infections may have contributed to the duration of protective NoV-specific immune responses that lasted for several years. This study adds to current understanding of the duration of passive protection by maternal antibodies and the duration and quality of acquired immunity following primary and subsequent NoV infections in infants and young children, who are the main target group for NoV vaccine development.
authors.affiliation: Vaccine Research Center, University of Tampere Medical School, Tampere, Finland.
authors.forename: Vesna
authors.initials: V
authors.lastname: Blazevic
authors.affiliation: Vaccine Research Center, University of Tampere Medical School, Tampere, Finland. Electronic address: maria.malm@uta.fi.
authors.forename: Maria
authors.initials: M
authors.lastname: Malm
authors.affiliation: Department of Virology, University of Tampere Medical School, Tampere, Finland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Honkanen
authors.affiliation: Tampere Centre for Child Health Research, Tampere University Hospital, Tampere, Finland; Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Research Programs Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland; Folkhälsan Research Centre, Helsinki, University of Helsinki, Finland.
authors.forename: Mikael
authors.initials: M
authors.lastname: Knip
authors.affiliation: Department of Virology, University of Tampere Medical School, Tampere, Finland; Fimlab Laboratories, Pirkanmaa Hospital District, Tampere, Finland.
authors.forename: Heikki
authors.initials: H
authors.lastname: Hyöty
authors.affiliation: Vaccine Research Center, University of Tampere Medical School, Tampere, Finland.
authors.forename: Timo
authors.initials: T
authors.lastname: Vesikari
mesh_terms: D000367:Age Factors; D019138:Antibodies, Blocking / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D000915:Antibody Affinity; D002648:Child; D002675:Child, Preschool; D004198:Disease Susceptibility; D064368:Healthy Volunteers; D006801:Humans; D007112:Immunity, Maternally-Acquired; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D029322:Norovirus / Q000276:immunology*; D011446:Prospective Studies
chemical_list: D019138:Antibodies, Blocking; D000914:Antibodies, Viral; D007074:Immunoglobulin G
keywords: Children; Immunity; Infant; Infections; Norovirus; Serology