Development of a sandwich ELISA for determining plasma prolactin concentration in domestic birds.

The present study was conducted to establish a sandwich ELISA for the determination of prolactin (PRL) concentrations in the plasma of domestic fowls. The assay uses a recombinant goose PRL as the reference standard, expressed in a eukaryotic system, and as the antigen for raising a polyclonal antibody in rabbit. This rabbit anti-goose PRL polyclonal antibody was used for coating the wells of the ELISA plate, and its biotinylated form served as the detection antibody. An avidin-conjugated horseradish peroxidase was used to bind the detection antibody and to catalyze the chromogenic reaction using 3,3',5,5'-tetramethylbenzidine as the substrate. The assay showed a linear relationship between the optical density and concentration of the standard PRL in the 0 to 12.5 ng/mL range, and the assay was sensitive to a concentration as low as 0.39 ng/mL. The intra- and inter-assay CVs were <7% and 11%, respectively. The response curves of the serially diluted plasma samples from goose, duck, and chicken exhibited similar parallel relationships to that observed for the reference standards. Consistent with previous findings, the assay effectively detected differences in PRL concentration in plasma samples from chicken, duck, and goose at various reproductive stages.