Non-Instrumental Immunoassay Based on Coloured Polyacrolein Latex: Application to Group-Specific Polysaccharide ofStreptococcus Pyogenes

摘要

Non-instrumental immunoassay methods based on immunofiltration and microtiter particle agglutination (MPA) techniques have been developed using coloured polyacrolein latex. These methods have been applied to the quantification of the group-specific polysaccharide, A-PS, ofS. pyogenes(group A Streptococcus) and compared to the standard ELISA tests. The assay with the ability to detect the lowest concentration of antigen was MPA; as little as 0.05 ng A-PS/ml or 104cells/ml could be detected in 1.5 h. In comparison to ELISA test the sensitivity of MPA was 10 times higher and the procedure of the assay was much more simple. The sensitivity of the immunofiltration assay using both enzyme and latex markers was shown to be the same (50 ng A-PS/ml) and the duration of the assay 3#x2013;5 min. No cross-reactions of latex conjugates with non A Streptococcus cell lysates have been observed. The developed methods are easy to perform and require neither sophisticated equipment nor specially trained personal.