title: Study of avidity of antigen-specific antibody as a means of understanding development of long-term immunological memory after Vibrio cholerae O1 infection.
abstract: The avidity of antibodies to specific antigens and the relationship of avidity to memory B cell responses to these antigens have not been studied in patients with cholera or those receiving oral cholera vaccines. We measured the avidity of antibodies to cholera toxin B subunit (CTB) and Vibrio cholerae O1 lipopolysaccharide (LPS) in Bangladeshi adult cholera patients (n = 30), as well as vaccinees (n = 30) after administration of two doses of a killed oral cholera vaccine. We assessed antibody and memory B cell responses at the acute stage in patients or prior to vaccination in vaccinees and then in follow-up over a year. Both patients and vaccinees mounted CTB-specific IgG and IgA antibodies of high avidity. Patients showed longer persistence of these antibodies than vaccinees, with persistence lasting in patients up to day 270 to 360. The avidity of LPS-specific IgG and IgA antibodies in patients remained elevated up to 180 days of follow-up. Vaccinees mounted highly avid LPS-specific antibodies at day 17 (3 days after the second dose of vaccine), but the avidity waned rapidly to baseline by 30 days. We examined the correlation between antigen-specific memory B cell responses and avidity indices for both antigens. We found that numbers of CTB- and LPS-specific memory B cells significantly correlated with the avidity indices of the corresponding antibodies (P < 0.05; Spearman's ρ = 0.28 to 0.45). These findings suggest that antibody avidity after infection and immunization is a good correlate of the development and maintenance of memory B cell responses to Vibrio cholerae O1 antigens.
authors.affiliation: Centre for Vaccine Sciences, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.
authors.forename: Mohammad Murshid
authors.initials: MM
authors.lastname: Alam
authors.forename: Mohammad
authors.initials: M
authors.lastname: Arifuzzaman
authors.forename: Shaikh Meshbahuddin
authors.initials: SM
authors.lastname: Ahmad
authors.forename: M Ismail
authors.initials: MI
authors.lastname: Hosen
authors.forename: Mohammad Arif
authors.initials: MA
authors.lastname: Rahman
authors.forename: Rasheduzzaman
authors.initials: R
authors.lastname: Rashu
authors.forename: Alaullah
authors.initials: A
authors.lastname: Sheikh
authors.forename: Edward T
authors.initials: ET
authors.lastname: Ryan
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Calderwood
authors.forename: Firdausi
authors.initials: F
authors.lastname: Qadri
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000276:immunology*; D000915:Antibody Affinity; D000942:Antigens, Bacterial / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D001459:Bangladesh; D002771:Cholera / Q000276:immunology; D002772:Cholera Toxin / Q000276:immunology; D022121:Cholera Vaccines / Q000008:administration & dosage / Q000276:immunology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007156:Immunologic Memory; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D008875:Middle Aged; D041241:Vibrio cholerae O1 / Q000276:immunology*; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D022121:Cholera Vaccines; D008070:Lipopolysaccharides; D002772:Cholera Toxin