title: Specificity of subcapsular antibody responses in Ethiopian patients following disease caused by serogroup A meningococci.
abstract: Dissecting the specificities of human antibody responses following disease caused by serogroup A meningococci may be important for the development of improved vaccines. We performed a study of Ethiopian patients during outbreaks in 2002 and 2003. Sera were obtained from 71 patients with meningitis caused by bacteria of sequence type 7, as confirmed by PCR or culture, and from 113 Ethiopian controls. Antibody specificities were analyzed by immunoblotting (IB) against outer membrane antigen extracts of a reference strain and of the patients' own isolates and by enzyme-linked immunosorbent assay for immunoglobulin G (IgG) levels against lipooligosaccharide (LOS) L11 and the proteins NadA and NspA. IB revealed that the main antigens targeted were the proteins PorA, PorB, RmpM, and Opa/OpcA, as well as LOS. MenA disease induced significant increases in IgG against LOS L11 and NadA. The IgG levels against LOS remained elevated following disease, whereas the IgG anti-NadA levels returned to acute-phase levels in the late convalescent phase. Among adults, the anti-LOS IgG levels were similar in acute-phase patient sera as in control sera, whereas anti-NadA IgG levels were significantly higher in acute-phase sera than in controls. The IgG antibody levels against LOS and NadA correlated moderately but significantly with serum bactericidal activity against MenA strains. Future studies on immune response during MenA disease should take into account the high levels of anti-MenA polysaccharide IgG commonly found in the population and seek to clarify the role of antibodies against subcapsular antigens in protection against MenA disease.
authors.affiliation: Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Gunnstein
authors.initials: G
authors.lastname: Norheim
authors.forename: Abraham
authors.initials: A
authors.lastname: Aseffa
authors.forename: Mohammed Ahmed
authors.initials: MA
authors.lastname: Yassin
authors.forename: Getahun
authors.initials: G
authors.lastname: Mengistu
authors.forename: Afework
authors.initials: A
authors.lastname: Kassu
authors.forename: Dereje
authors.initials: D
authors.lastname: Fikremariam
authors.forename: Wegene
authors.initials: W
authors.lastname: Tamire
authors.forename: Yared
authors.initials: Y
authors.lastname: Merid
authors.forename: E Arne
authors.initials: EA
authors.lastname: Høiby
authors.forename: Dominique A
authors.initials: DA
authors.lastname: Caugant
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Fritzsønn
authors.forename: Torill
authors.initials: T
authors.lastname: Tangen
authors.forename: Berhanu
authors.initials: B
authors.lastname: Melak
authors.forename: Degu
authors.initials: D
authors.lastname: Berhanu
authors.forename: Morten
authors.initials: M
authors.lastname: Harboe
authors.forename: Jan
authors.initials: J
authors.lastname: Kolberg
authors.forename: Einar
authors.initials: E
authors.lastname: Rosenqvist
mesh_terms: D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000097:blood*; D000917:Antibody Formation; D000918:Antibody Specificity; D000942:Antigens, Bacterial; D016667:Bacterial Capsules / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005002:Ethiopia / Q000453:epidemiology; D006801:Humans; D007074:Immunoglobulin G; D008070:Lipopolysaccharides / Q000032:analysis / Q000276:immunology* / Q000378:metabolism; D008585:Meningitis, Meningococcal / Q000453:epidemiology / Q000276:immunology*; D038381:Neisseria meningitidis, Serogroup A / Q000235:genetics / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; C023023:lipid-linked oligosaccharides