High Antibody-Dependent Cellular Cytotoxicity Antibody Titers to H5N1 and H7N9 Avian Influenza A Viruses in Healthy US Adults and Older Children

• Published in: The Journal of infectious diseases Vol. 212; no. 7; pp. 1052 - 1060
• Main Authors: Terajima, Masanori, Dawn, Mary, Cruz, John, Ennis, Francis A.
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01-10-2015
• Subjects: Adolescent; Adult; Antibodies, Viral - blood; Antibody-Dependent Cell Cytotoxicity - immunology; Child; Child, Preschool; Complement System Proteins - immunology; Hemagglutination Tests; Humans; Infant; Influenza A virus; Influenza A Virus, H5N1 Subtype - immunology; Influenza A Virus, H7N9 Subtype - immunology; Influenza, Human - immunology; Influenza, Human - prevention & control; Killer Cells, Natural - immunology; Major and Brief Reports; Middle Aged; VIRUSES; Young Adult; USA; antibody-dependent cellular cytotoxicity; H7N9 subtype; H5N1 subtype; antibody-dependent cell-mediated cytotoxicity; avian influenza viruses; non-neutralizing antibody; ADCC, complement-dependent lysis; hemagglutination-inhibition
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1093/infdis/jiv181

Human influenza is a highly contagious acute respiratory illness that is responsible for significant morbidity and excess mortality worldwide. In addition to neutralizing antibodies, there are antibodies that bind to influenza virus–infected cells and mediate lysis of the infected cells by natural killer (NK) cells (antibody-dependent cellular cytotoxicity [ADCC]) or complement (complement-dependent lysis [CDL]). We analyzed sera obtained from 16 healthy adults (18-63 years of age), 52 children (2-17 years of age), and 10 infants (0.75-1 year of age) in the United States, who were unlikely to have been exposed to the avian H7N9 subtype of influenza A virus, by ADCC and CDL assays. As expected, none of these sera had detectable levels of hemagglutination-inhibiting antibodies against the H7N9 virus, but we unexpectedly found high titers of ADCC antibodies to the H7N9 subtype virus in all sera from adults and children aged ≥8 years.