Enzyme-linked immunosorbent assay for detection of Pseudomonas aeruginosa Lipopolysaccharides

A double-antibody sandwich method of enzyme-linked immunosorbent assay was developed to detect lipopolysaccharides (LPS) from the eight most prevalent Pseudomonas aeruginosa serotypes (O1, O2,5,16, O3, O4, O6, O9, O10, and O11). Immunoglobulin M fractions from rabbit antisera were used as the coating antibody and as the antibody to be conjugated to an enzyme. When two fractions of LPS (I and II) obtained by Sepharose 2B column chromatography were assayed, LPS II showed 10 to 100 times more activity than LPS I; the detection level of LPS II was 0.1 ng/ml. When LPS in purified preparations or in culture filtrates was examined with both homologous and heterologous antibody systems, the same specificity pattern was demonstrated, suggesting that, in crude filtrates, antigens other than LPS do not interfere in the assay. The method described can be used to detect LPS in biological fluids.