Anti-Pseudomonas aeruginosa IgG ELISA

The assay is a sandwich enzyme immunoassay. Serum or plasma samples are diluted and added to the wells of a microtiter plate, which have been previously coated with the Pseudomonas aeruginosa antigens alkaline protease, elastase, or exotoxin A. Specific antibodies in the sample bind to the respective antigens during an incubation of 2 h at 37°C. After washing, the conjugate (peroxidase-labelled anti-human IgG immunoglobulin) is added and incubated again for 2 h at 37°C. After a final washing step, substrate is added and incubated for 30 min at room temperature. The color forming reaction is terminated on addition of stop solution accompanied by a color change from blue to yellow. The absorbance of the colored reaction product is measured on a microtiter plate reader. The color intensity of the reaction corresponds to the concentration of antibodies in the sample.