Two enzyme linked immunosorbent assays for detecting antibodies against meningococcal capsular polysaccharides A and C
| Autor: | D. S. Kumararatne, D. Catty, D. M. Goodall, O. A. O. Akinwolere, R. Bartlett |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Titration curve
Serum albumin Enzyme-Linked Immunosorbent Assay Neisseria meningitidis medicine.disease_cause Polysaccharide Pathology and Forensic Medicine Sepharose Antigen Antibody Specificity medicine Humans Polylysine Serum Albumin chemistry.chemical_classification biology Polysaccharides Bacterial Reproducibility of Results General Medicine Human serum albumin Antibodies Bacterial Molecular biology chemistry biology.protein Antibody Research Article medicine.drug |
| Zdroj: | Journal of Clinical Pathology. 47:405-410 |
| ISSN: | 0021-9746 |
| Popis: | AIMS--To evaluate two of the recent methods of coating microtitre plates in the enzyme linked immunosorbent assay (ELISA) for detecting human antibodies against meningococcal capsular polysaccharides A and C with a view to validating a specific meningococcal antibody assay for routine clinical use. METHODS--Two four-layer ELISA protocols were standardised: one method utilised meningococcal polysaccharides conjugated to poly-L-lysine polypeptide for coating the microtitre plates; another used polysaccharides mixed with methylated human serum albumin (mHSA). Titration curves were plotted for the ELISAs and the squared Pearson correlation coefficient (R2) was used to determine the degree of accuracy of fit of the curves. Specificity tests were performed by inhibition and adsorption studies. RESULTS--Both methods gave good titration curves with a high R2 of > 0.98, indicating a high degree of accuracy in forming the curves. The titration end point after vaccination, obtained by the mHSA method, was 20 times higher, however, than that obtained by the poly-L-lysine method. Specificity tests showed that in the ELISA using polysaccharide/poly-L-lysine, antibody activity of a pre-vaccination serum sample was inhibited by 37%, and of post-vaccination serum by 50% with 1000-fold excess antigen. Antibody activity (post-vaccination) was reduced by 51% and 59%, respectively, by adsorption with antigen-coated Sepharose beads or adsorption with suspensions of killed meningococci. In contrast, antibody activity of a pre-vaccination serum was inhibited by 60% and a post-vaccination serum by 90% in ELISA employing polysaccharides mixed with mHSA. Reproducibility was better with the use of methylated human serum albumin than with poly-L-lysine; the former showed intrabatch and interbatch coefficients of variation of 4% and 2%, respectively, compared with 43% (intrabatch) and 16% (interbatch) obtained with the poly-L-lysine. CONCLUSION--It is concluded that the antibody assay using meningococcal polysaccharides groups A and C mixed with mHSA is much better than that using polysaccharides coupled with poly-L-lysine. |
| Databáze: | OpenAIRE |
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