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Avidity of IgG Antibodies Against Meningococcal Serogroup A Polysaccharide and Correlations with Bactericidal Activity in Sera From Meningitis Patients and Controls From E thiopia
Author(s) -
Medhane M.,
Tunheim G.,
Næss L. M.,
Mihret W.,
Bedru A.,
Norheim G.,
Petros B.,
Aseffa A.,
Rosenqvist E.
Publication year - 2014
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/sji.12150
Subject(s) - avidity , antibody , meningococcal meningitis , meningitis , meningococcal disease , immunology , medicine , virology , neisseria meningitidis , microbiology and biotechnology , biology , bacteria , psychiatry , genetics
Abstract Meningococcal meningitis is a significant global health challenge, especially for sub‐Saharan area: the African meningitis belt. N eisseria meningitidis of serogroup A (MenA) is responsible for the large number of epidemics that have been recorded in these countries. To determine the level of antibodies against meningococcal A polysaccharide ( APS ) that correlates with protection against MenA disease in the A frican meningitis belt, it may be important to consider antibody avidity along with quantity. In this study, two ELISA methods using the chaotropic agent ammonium thiocyanate were compared and employed to measure avidity indexes ( AI ) of IgG antibodies against APS in controls and in acute and convalescent sera from Ethiopian meningococcal patients. High statistical correlations between the AI s determined by the two methods were observed. The geometric mean AI ( GMAI ) increased with time from acute to convalescent sera indicating affinity maturation. GMAI was significantly higher in convalescent sera from the MenA patients and in sera from the controls than in acute sera from patients with meningococcal disease. A significant correlation between serum bactericidal activity titres ( SBA ) and concentration of IgG antibodies against APS was observed; however, our results did not indicate that determination of antibody avidities by the thiocyanate elution method gave a better correlation with SBA than anti‐ APS IgG concentrations determined by the standard ELISA method.