title: Enhancement of neutralizing activity of influenza virus-specific antibodies by serum components.
abstract: The role of serum components in enhancing virus neutralizing (VN) activity of influenza virus A/PR/8/34 hemagglutinin (HA)-specific MAbs in vitro was investigated. The degree of enhancement depended on the MAb's fine specificity and heavy chain isotype and on type of serum. Greatest enhancement (>100-fold) was seen with sera from immunodeficient mice that lacked serum immunoglobulin. At least two serum components were involved: C1q and a heat-resistant factor. C1q was mandatory for enhancement, and other components of the complement system were not required. C1q appeared to operate by improving MAb-mediated inhibition of virus attachment to host cells and was most effective with MAbs that inhibited virus attachment poorly on their own. The heat-resistant factor enhanced VN activity only in the presence of C1q and appeared to operate by enhancing VN activity at a post-attachment stage.
authors.affiliation: Immunology Program, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104-4268, USA.
authors.forename: Krystyna
authors.initials: K
authors.lastname: Mozdzanowska
authors.forename: Jingqi
authors.initials: J
authors.lastname: Feng
authors.forename: Mark
authors.initials: M
authors.lastname: Eid
authors.forename: Darya
authors.initials: D
authors.lastname: Zharikova
authors.forename: Walter
authors.initials: W
authors.lastname: Gerhard
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral / Q000097:blood*; D000918:Antibody Specificity; D000956:Antigens, Viral / Q000737:chemistry; D002460:Cell Line; D015922:Complement C1q / Q000378:metabolism; D003176:Complement C3 / Q000378:metabolism; D004285:Dogs; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry / Q000276:immunology*; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D016513:Mice, SCID; D018448:Models, Immunological; D008958:Models, Molecular; D009500:Neutralization Tests
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D003176:Complement C3; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D015922:Complement C1q