title: Secretory immunological response in infants and children to parainfluenza virus types 1 and 2.
abstract: The secretory immunological responses to natural infection with parainfluenza viruses ae not well defined. Nasopharyngeal secretion specimens from 20 infants and children naturally infected with parainfluenza virus type 1 or type 2 were examined for class-specific antibody and virus-neutralizing activity. There was a marked discordance in individual secretions between immunoglobulin A (IgA) antibody (as measured by indirect immunofluorescence) and neutralizing activity (as determined by either hemadsorption plaque or 50% tissue culture infective dose reduction) to the infecting parainfluenza virus type. Many secretions contained neutralizing activity in the absence of detectable IgA antibody; conversely, secretions with measureable IgA antibody frequently lacked neutralizing activity. Moreover, there was no relationship between neutralizing activity and the course of illness. All 11 patients with serial secretion specimens showed a fourfold or greater titer rise in IgA antibody to the homologous parainfluenza virus type. Antibody usually appeared 7 to 10 days after the onset of symptoms and peaked at about 2 weeks. This response did not appear to be related to age or to severity of illness. in general, the secretory responses resembled those seen in infants infected with respiratory syncytial virus.
mesh_terms: D000910:Antibodies, Heterophile / Q000096:biosynthesis; D000914:Antibodies, Viral / Q000096:biosynthesis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000096:biosynthesis*; D007071:Immunoglobulin A, Secretory / Q000096:biosynthesis*; D007136:Immunoglobulins / Q000096:biosynthesis; D007223:Infant; D008297:Male; D009297:Nasal Mucosa / Q000378:metabolism; D009500:Neutralization Tests; D010222:Parainfluenza Virus 1, Human / Q000276:immunology*; D010223:Parainfluenza Virus 2, Human / Q000276:immunology*; D018184:Paramyxoviridae Infections / Q000276:immunology*; D018108:Respirovirus / Q000276:immunology*; D013997:Time Factors
chemical_list: D000910:Antibodies, Heterophile; D000914:Antibodies, Viral; D007070:Immunoglobulin A; D007071:Immunoglobulin A, Secretory; D007136:Immunoglobulins