New Immunoassay Platform Utilizing Yeast Surface Display and Direct Cell Counting

摘要

In this study, we report a new immunoassay platformnusing yeast cell surface display. This method holdsnpromise for very low limit of detection (LOD) and isnsuitable for 2-Plex antibody recognition. Instead of adoptingna conventional enzyme linked immunosorbent assayn(ELISA) protocol by detecting the enzymatic activities ornother physicochemical properties of the labeled analytes,nthis approach determines the quantity of an antibodynanalyte by directly counting the amount of “modified”nyeast cells bound with antibody on the cell surface. c-mycnand hemagglutinin (HA) tags were employed as an epitopenmodel to demonstrate our approach. This yeast surfacendisplay based cell counting immunoassay (abbreviated asnYSD-CCI) for anti-c-myc has a detection limit of 0.2 ngmL, which is about 80 times higher than that of a conventionalnyeast ELISA under a similar condition. Moreover, thenYSD-CCI’s capability for 2-Plex antibody detection wasndemonstrated by simultaneous detection of anti-c-myc andnanti-HA using engineered yeast cells expressing intracellularnenhanced green fluorescent protein (EGFP) and mCherry,nrespectively. This proof-of-concept study paves the way forna new ultrasensitive multiplexed immunoassay method forndiagnostic applications.