Secretory IgA- and IgG-coated bacteria in the nasopharynx of children. An immunofluorescence study.
Bacterial samples were obtained from the posterior wall of the nasopharynx (NPH) of 18 healthy children (age range 1 to 14 years, 10 males, 8 females) and subjected for immunofluorescence studies using fluorescein-labelled goat anti-human IgG and goat anti-human SIgA antibodies. Quantitative and qualitative bacteriological analyses were performed simultaneously. IgG-coated bacteria in the NPH were observed in 1-year-old subjects and opsonized bacteria seemed to increase in numbers and fluorescence intensity with increasing age. SIgA-coated bacteria appeared later, and intensely fluorescing bacteria were not seen until the age of 3 to 6 years. Thirteen out of the 18 children harboured middle ear pathogens in the NPH, but generally speaking non-pathogens dominated the bacterial flora. Immunoglobulins are of the utmost importance for the mucosal defence system, including protection against bacterial attachment to the epithelial cells (SIgA), and bacteriolysis and opsonization of the bacteria (IgG).
Stenfors
L E
LE
Department of Otolaryngology, University of Tromsö, Norway.
Räisänen
S
S
D002648:Child; D002675:Child, Preschool; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D009092:Mucous Membrane / Q000276:immunology; D009305:Nasopharynx / Q000382:microbiology*; D009895:Opsonin Proteins / Q000276:immunology; D010033:Otitis Media / Q000382:microbiology; D010587:Phagocytosis
D007071:Immunoglobulin A, Secretory; D007074:Immunoglobulin G; D009895:Opsonin Proteins