A solid-phase radioimmunoassay for bacterial lipopolysaccharide.

A radioimmunoassay for E. coli 055:B5 lipopolysaccharide (LPS) is described. The LPS was derivatised by two new methods and subsequently radiolabeled with 125I to a specific activity of 2-4 mCi/mg without apparent loss in its biophysical, immunological or biological activities. Using antibody-coated polystyrene tubes, a solid-phase radioimmunoassay was developed with a sensitivity of 10-500 ng/ml of LPS.