earticle

영어

The Z-domain of protein A has been known to bind specifically to the Fc region of antibodies (IgG’s)1). In this work, the Z-domain of protein A was expressed on the outer membrane of E.coli by using “Autodisplay” technology as a fusion protein of autotransport domain2). The E.coli with autodisplayed Z-domain was applied to the sandwich-type immunoassay as a solid-support of detection-antibodies against a target analyte. For the feasibility demonstration of the E.coli based immunoassay, C-reactive protein (CRP) assay was carried out by using E.coli with autodisplayed Z-domain. The limit of detection (LOD) and binding capacity of the E.coli based immunoassay was estimated to be far more sensitive than the conventional ELISA. Such
a far higher sensitivity of E.coli based immunoassay than conventional ELISA was explained by the difference of analyte binding sites and the mobility of E.coli in assay matrix. From the test results of 45 RA patients’ serum and 15 healthy samples, a cut-off value was established to have optimal sensitivity and selectivity values for RA3). The CRP test result of each individual sample was compared with ELISA which is the reference method for RA diagnosis. From this
work, the E.coli with Z-domain was was proved to be feasible for the medical diagnosis based on sandwich-type immunoassay.