Virus-coated layer-by-layer colloids as a multiplex suspension array for the detection and quantification of virus-specific antibodies.

BACKGROUND Suspension array technology has surpassed ELISA for automated, simultaneous detection and quantification of soluble biomarkers such as virus-specific antibodies. We describe assays in which antigens are attached to a lipid bilayer surrounding color-coded particles. METHODS We used layer-by-layer technology to establish a multiplex suspension array with distinguishable microbeads coated with authentic viral surfaces to catch and quantify virus-specific antibodies in a flow cytometric analysis. Antigenic surfaces were generated by chimeric and wild-type baculoviruses plus 2 different influenza A virus subtypes fused to a lipid bilayer surrounding distinctly colored particles. Specificity of binding of chosen antibodies and sera was detected by immunofluorescence. Results of multiplex analysis were compared with results of ELISA. RESULTS Titrations of virus-specific antibodies in the multiplex suspension array demonstrated specific binding to the viral surface proteins. The multiplex suspension array gave positive results for up to log 5-diluted primary antibodies with an approximately 5- to 10-fold reduced dynamic range compared with the respective ELISA. CONCLUSIONS The bead-based multiplex suspension array is customizable and easy to establish. By displaying native influenza A virus surfaces and recombinant HIV-1 epitopes, the new assay provides a tool for the detection of major viral infections in humans.