A sensitive direct ELISA for detection of prostaglandin E2

In order to improve the indirect ELISA for detection of PGE(2), a modified direct ELISA technique was developed to measure PGE(2) in cell culture supernatants. An evaluation of three types of coating buffer showed that PGE(2) was adsorbed efficiently to the solid phase using the gelatin phosphate buffer. The sensitivity of the assay was increased by employing polyclonal rabbit anti-PGE(2) antibody dilution of 1/100 and 1% skimmed milk as a blocking solution, with the detection limit of 7.8-500 ng/well. The within-run and between-run coefficients of variation (CV) ranges were 3.2-3.7% and 3.4-3.8%, respectively. A linear standard curve was observed over the range of 0.078-5 mg/mL with a coefficient of determination (r(2)) of 0.99. Our results indicated that the developed direct ELISA was sensitive and suitable for a quick determination of PGE2 levels from cell culture supernatants.