Immunoassay of HumanNeisseria MeningitidisSerogroup a Antibody

Abstract

An enzyme immunoassay is described which quantitates antibodies to Neisseria meningitidis serogroup A capsular polysaccharide in human sera. Modifications of a previously developed two-day assay by Carlone et al. were made to permit analysis in one day and to be compatible with automation. The allowable variations in assay conditions and the areas in which stringent control must be maintained for consistent assay performance are described. Antigen-coating parameters, the kinetics of primary and secondary antibody incubation steps, the buffer compositions, including detergents, serum requirements, and the need for blocking steps were examined. Our modified one-day assay showed excellent agreement with the standardized method of Carlone, with a correlation coefficient between the two methods of 0.989. This assay is adaptable within a permissible range of parameters thus facilitating the implementation of the standardized assay. This will maximize the consistency of results from serum analysis for conjugate vaccine trials related to serotype A Neisseria meningitidis.

Assignment ofNeisseria meningitidisSerogroups A, C, W135, and Y Anticapsular Total Immunoglobulin G (IgG), IgG1, and IgG2 Concentrations to Reference Sera

“…An IgG2 response is thought to involve limited T cell help for B cell antibody production (1). This is reflected in the response to meningococcal polysaccharide and conjugate vaccines, where the polysaccharide response is T cell independent and short term (6), but the conjugate vaccine stimulates a T-cell-dependent response, priming immunological memory. Therefore, it would be of interest to analyze the IgG subclass response to both types of vaccine.…”

Imunogenicidade de antígenos de vesículas de membrana externa (OMVs) de Neisseria meningitidis B associada a lípide catiônico (DDA-BF).

“…Na análise do isótipo IgG2a, 60 dias após a primeira imunização, embora os dois grupos tenham produzido este isótipo de IgG, apenas nos animais imunizados com H.A./OMVs apresentaram em seus soros, níveis de anticorpos significativamente superiores em relação aos dos controles, porém também não houve diferença estatística na produção de IgG2b entre os grupos imunizados com DDA-BF/OMVs e H.A./OMVs, sendo que o grupo H.A./OMVs apresentou maior título. O isótipo IgG2a tem grande importância ao se tratar de imunidade duradoura, da qual indica resposta do tipo Th1, como comentado anteriormente(DIAKUN et al, 1997). A. foram capazes de gerar imunidade celular após uma dose das preparações antigênicas recebidas (DDA-BF/OMVs e H.A./OMVs).…”