Enzyme linked immunosorbent assay for human apolipoprotein C-III.

A sandwich enzyme linked immunosorbent assay (ELISA) for apolipoprotein C-III was developed. Anti apolipoprotein C-III immunoglobulins were used both for coating of microtitre plates and for the preparation of an anti apolipoprotein C-III horse-radish peroxidase conjugate. Under optimized assay conditions, the sensitivity lies around 0.3 ng apolipoprotein C-III with a working range of 1 to 6 ng. Standard curves are parallel for purified apolipoprotein C-III, for untreated plasma and for lipoprotein fractions. Delipidation did not affect the content of apolipoprotein C-III in plasma. The assay was evaluated by comparison with an immunonephelometric assay for apolipoprotein C-III, yielding a correlation coefficient of 0.982 (n = 79). The mean intra- and interassay CV for the whole working range of the assay were 3.6% and 4.2% respectively.