title: Antibody response after RSV infection in children younger than 1 year of age living in a rural area of Mozambique.
abstract: Serological responses have been studied in respiratory syncytial virus (RSV) infected children < 1 year of age attending the outpatient department of the Manhiça District Hospital (Mozambique). Molecular characterization of viral RNA in nasopharyngeal aspirates from the infected children indicated a high level of genetic uniformity among the infecting viruses, all of which belonged to a single genotype of RSV group A. A representative virus strain, Moz00, was isolated from one of the infants and was used, together with the group A strain A2 and the group B strain 8/60, as antigens in the quantification of infant antibody responses. In this study, 97.5% (39/40) and 96.4% (27/28) of infected children produced an antibody response against Moz00 detected by the membrane fluorescent antibody test (MFAT) and the neutralization test (NT), respectively. Seroconversion rates decreased when the A2 and 8/60 strains were used as antigen in MFAT (95.4% and 88.2%, respectively) or NT (81.8% and 54.5%, respectively), indicating that antibody responses had both group- and strain-specific components. Antibodies in convalescent sera of infected children were compared with maternally derived antibodies detected in a group of children also < 1 year of age, but with no evidence of RSV infection. The convalescent sera exhibited reduced neutralizing capacity when the 8/60 strain was used as antigen (P = 0.028), suggesting that the infant antibody response lacks neutralizing capacity against strains of the heterologous virus group. Restricted cross-reactivity and neutralizing capacity of antibodies generated by young children might be expected to induce only moderate protection in subsequent epidemics against genetically distant strains.
authors.affiliation: Unitat d'Epidemiologia i Bioestadística-UASP, Hospital Clinic, Universitat de Barcelona, Spain. aroca@medicina.ub.es
authors.forename: Anna
authors.initials: A
authors.lastname: Roca
authors.forename: Llorenç
authors.initials: L
authors.lastname: Quintó
authors.forename: Fátima
authors.initials: F
authors.lastname: Abacassamo
authors.forename: Maria Paz
authors.initials: MP
authors.lastname: Loscertales
authors.forename: Francesc Xavier
authors.initials: FX
authors.lastname: Gómez-Olivé
authors.forename: Fiona
authors.initials: F
authors.lastname: Fenwick
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Cane
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Saiz
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Toms
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Alonso
mesh_terms: D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000097:blood*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008969:Molecular Sequence Data; D009073:Mozambique / Q000453:epidemiology; D012150:Polymorphism, Restriction Fragment Length; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology* / Q000276:immunology / Q000821:virology; D012136:Respiratory Syncytial Viruses / Q000145:classification / Q000235:genetics / Q000276:immunology*; D012424:Rural Population; D017422:Sequence Analysis, DNA; D016036:Seroepidemiologic Studies; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D000914:Antibodies, Viral; D014764:Viral Proteins