Direct double antibody sandwich immunoassay for Pseudomonas aeruginosa elastase

A direct sandwich enzyme immunoassay was developed in order to quantify Pseudomonas aeruginosa elastase. As a solid phase the wells of a microtitre plate were coated with specific IgG and horseradish peroxidase labelled IgG was used as the second antibody. The detection limit of the assay was 0.26 ng/ml and a good agreement was found with elastolytic activity determined using elastin-Congo red. This assay was simple, specific, sensitive and reproducible, and permits the determination of low levels of elastase.