An enzyme-linked immunosorbent assay (ELISA) for the quantitation of urinary desmosine

An enzyme-linked immunosorbent assay (ELISA) method has been developed for the quantitation of the elastin cross-link desmosine in urine. The system employs Rabbit antisera directed to the conjugate of desmosine and bovine serum albumin which was conjugated using carbodiimide reagent. The ELISA was done in microtiter plates which were coated with a desmosine-gelatin conjugate. And the assay system is based on an inhibition immunoassay. With this assay system, desmosine could be detected in a range between 0.4-400 ng/ml. Recovery of desmosine (DES) added to urine was 90.6-117.0% as measured by this method. Anti-DES antisera obtained from rabbits, showed no cross-reaction to 19 standard amino acids, two elastines nor mouse acetone liver power (which contained degradated elastin). But iso-desmosine cross-reacted with the antisera 13-45% at the isodesmosine concentration range of 40-400 ng/ml. Column purification of the urinary desmosine with CF-1 cellulose will not be necessary for desmosine measurement in ELISA assay. This paper described the detail procedures for sample preparation and the desmosine measurement in urine. Desmosine measurement can be an effective marker for screening the lung elastin degradation caused by cigarette smoking and environmental pollution to human lung.