title: The transfer and decay of maternal antibody against Shigella sonnei in a longitudinal cohort of Vietnamese infants.
abstract: BACKGROUND
  Shigella sonnei is an emergent and major diarrheal pathogen for which there is currently no vaccine. We aimed to quantify duration of maternal antibody against S. sonnei and investigate transplacental IgG transfer in a birth cohort in southern Vietnam.
  
  
  RESULTS
  Over 500-paired maternal/infant plasma samples were evaluated for presence of anti-S. sonnei-O IgG and IgM. Longitudinal plasma samples allowed for the estimation of the median half-life of maternal anti-S. sonnei-O IgG, which was 43 days (95% confidence interval: 41-45 days). Additionally, half of infants lacked a detectable titer by 19 weeks of age. Lower cord titers were associated with greater increases in S. sonnei IgG over the first year of life, and the incidence of S. sonnei seroconversion was estimated to be 4/100 infant years. Maternal IgG titer, the ratio of antibody transfer, the season of birth and gestational age were significantly associated with cord titer.
  
  
  CONCLUSIONS
  Maternal anti-S. sonnei-O IgG is efficiently transferred across the placenta and anti-S. sonnei-O maternal IgG declines rapidly after birth and is undetectable after 5 months in the majority of children. Preterm neonates and children born to mothers with low IgG titers have lower cord titers and therefore may be at greater risk of seroconversion in infancy.
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK; London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Corinne N
authors.initials: CN
authors.lastname: Thompson
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam.
authors.forename: Thi Phuong Tu
authors.initials: TP
authors.lastname: Le
authors.affiliation: School of Biological Sciences, Monash University, Victoria, Australia.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Anders
authors.affiliation: Hung Vuong Hospital, Ho Chi Minh City, Viet Nam.
authors.forename: Trong Hieu
authors.initials: TH
authors.lastname: Nguyen
authors.affiliation: The Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam.
authors.forename: Lan Vi
authors.initials: LV
authors.lastname: Lu
authors.affiliation: The Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam.
authors.forename: Van Vinh Chau
authors.initials: VV
authors.lastname: Nguyen
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam.
authors.forename: Thuy Duong
authors.initials: TD
authors.lastname: Vu
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam.
authors.forename: Ngoc Minh Chau
authors.initials: NM
authors.lastname: Nguyen
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam.
authors.forename: Thi Hong Chau
authors.initials: TH
authors.lastname: Tran
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam.
authors.forename: Thanh Tuyen
authors.initials: TT
authors.lastname: Ha
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam.
authors.forename: Vu Thieu Nga
authors.initials: VT
authors.lastname: Tran
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam.
authors.forename: Van Minh
authors.initials: VM
authors.lastname: Pham
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam.
authors.forename: Do Hoang Nhu
authors.initials: do HN
authors.lastname: Tran
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam.
authors.forename: Thi Quynh Nhi
authors.initials: TQ
authors.lastname: Le
authors.affiliation: Novartis Vaccines Institute for Global Health(2), A GSK Company, Siena, Italy.
authors.forename: Allan
authors.initials: A
authors.lastname: Saul
authors.affiliation: Novartis Vaccines Institute for Global Health(2), A GSK Company, Siena, Italy.
authors.forename: Laura B
authors.initials: LB
authors.lastname: Martin
authors.affiliation: Novartis Vaccines Institute for Global Health(2), A GSK Company, Siena, Italy.
authors.forename: Audino
authors.initials: A
authors.lastname: Podda
authors.affiliation: Novartis Vaccines Institute for Global Health(2), A GSK Company, Siena, Italy.
authors.forename: Christiane
authors.initials: C
authors.lastname: Gerke
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK.
authors.forename: Guy
authors.initials: G
authors.lastname: Thwaites
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK; Department of Microbiology and Immunology, University of Melbourne, Australia.
authors.forename: Cameron P
authors.initials: CP
authors.lastname: Simmons
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK; London School of Hygiene and Tropical Medicine, London, UK. Electronic address: sbaker@oucru.org.
authors.forename: Stephen
authors.initials: S
authors.lastname: Baker
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood* / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D006207:Half-Life; D006801:Humans; D007112:Immunity, Maternally-Acquired; D007074:Immunoglobulin G / Q000097:blood* / Q000737:chemistry; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D019081:O Antigens / Q000302:isolation & purification; D000069078:Seroconversion; D012764:Shigella sonnei; D014744:Vietnam
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D019081:O Antigens
keywords: Maternal antibody; Placental transfer; Seroconversion; Shigella