title: Antibody-dependent enhancement of respiratory syncytial virus infection by sera from young infants.
abstract: Respiratory syncytial virus (RSV) convalescent-phase sera and control sera from both infants ( < 6 months) and older individuals (1.5 to 90 years) were assayed for RSV-specific antibodies by neutralization, in vitro enhancing activity, and immunoprecipitation. Enhancement of RSV infection in U937 cells was demonstrated with convalescent-phase sera and was shown to be dependent on Fc receptors by blocking with human immunoglobulin G (P < 0.01). Convalescent-phase sera from infants enhanced infection at concentrations closer to physiological ones (10(-1) to 10(-3) dilutions of serum), while convalescent-phase sera from older individuals enhanced infection only at much lower concentrations (10(-3) to 10(-6) dilutions of serum; P < 0.01). To our knowledge, this is the first report of RSV-enhancing antibody activity in the sera of infants. The observed enhancing activity and the low neutralizing antibody levels are confined mostly to convalescent-phase sera from infants aged 0 to 6 months, suggesting that these factors may contribute to the increased severity of RSV disease frequently encountered in young infants.
authors.affiliation: Department of Microbiology and Infectious Disease, Faculty of Medicine, University of Calgary, Alberta, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Osiowy
authors.forename: D
authors.initials: D
authors.lastname: Horne
authors.forename: R
authors.initials: R
authors.lastname: Anderson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007201:Indicator Dilution Techniques; D007223:Infant; D007822:Laryngeal Neoplasms; D008875:Middle Aged; D009500:Neutralization Tests; D011233:Precipitin Tests; D011961:Receptors, Fc / Q000276:immunology; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology*; D018113:Respiratory Syncytial Virus, Human / Q000276:immunology*; D014407:Tumor Cells, Cultured / Q000276:immunology / Q000821:virology; D014759:Viral Envelope Proteins / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D011961:Receptors, Fc; D014759:Viral Envelope Proteins