title: Immune response to respiratory syncytial virus in young Brazilian children.
abstract: We have evaluated the cellular and humoral immune response to primary respiratory syncytial virus (RSV) infection in young infants. Serum specimens from 65 patients <=12 months of age (39 males and 26 females, 28 cases <3 months and 37 cases > or = 3 months; median 3 3.9 months) were tested for anti-RSV IgG and IgG subclass antibodies by EIA. Flow cytometry was used to characterize cell surface markers expressed on peripheral blood mononuclear cells (PBMC) from 29 RSV-infected children. There was a low rate of seroconversion in children <3 months of age, whose acute-phase PBMC were mostly T lymphocytes (63.0 +/- 9.0%). In contrast, a higher rate of seroconversion was observed in children >3 months of age, with predominance of B lymphocytes (71.0 +/- 17.7%). Stimulation of PBMC with RSV (2 x 10(5) TCID50) for 48 h did not induce a detectable increase in intracellular cytokines and only a few showed a detectable increase in RSV-specific secreted cytokines. These data suggest that age is an important factor affecting the infants' ability to develop an immune response to RSV.
authors.affiliation: Departamento de Imunologia, Microbiologia e Parasitologia, Instituto de Ci ncias Biom dicas, Universidade Federal de Uberl ndia, Uberl ndia, MG, Brasil. dqueiroz@icbim.ufu.br
authors.forename: D A O
authors.initials: DA
authors.lastname: Queiróz
authors.forename: E L
authors.initials: EL
authors.lastname: Durigon
authors.forename: V F
authors.initials: VF
authors.lastname: Botosso
authors.forename: B
authors.initials: B
authors.lastname: Ejzemberg
authors.forename: S E
authors.initials: SE
authors.lastname: Vieira
authors.forename: J R
authors.initials: JR
authors.lastname: Mineo
authors.forename: C
authors.initials: C
authors.lastname: Yamashita
authors.forename: N
authors.initials: N
authors.lastname: Hein
authors.forename: C L
authors.initials: CL
authors.lastname: Lopes
authors.forename: A L
authors.initials: AL
authors.lastname: Cacharo
authors.forename: K E
authors.initials: KE
authors.lastname: Stewien
mesh_terms: D000367:Age Factors; D000914:Antibodies, Viral / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D015415:Biomarkers; D001938:Brazil; D016207:Cytokines / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007111:Immunity, Cellular; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000276:immunology; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology*; D018113:Respiratory Syncytial Virus, Human / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D000954:Antigens, Surface; D015415:Biomarkers; D016207:Cytokines; D007074:Immunoglobulin G