Preparation and Application of Monoclonal Antibodies for an Immune Complex Transfer Enzyme Immunoassay of an Egg White Allergen, Lipocalin-Type Prostaglandin D Synthase.

We have previously reported that lipocalin-type prostaglandin D synthase (L-PGDS) in egg white reacts with IgE antibodies from children with egg allergies. However, antibodies against chicken L-PGDS are not commercially available, and the amount of L-PGDS in egg white is unclear. In this study, we prepared four monoclonal antibodies against chicken L-PGDS and developed a sandwich enzyme-linked immunosorbent assay (ELISA) and a highly sensitive immune complex transfer enzyme immunoassay (ICT-EIA) to quantify L-PGDS in hen egg whites. The detection sensitivity of ICT-EIA for L-PGDS (0.01 ng/mL) was 2,000-fold higher than that of ELISA, which could not be adapted to determine the amount of L-PGDS in egg white. Thus, ICT-EIA is a better method for quantification of trace allergens and expected to be applied to the quantification of other food allergens. Hen eggs (white-shelled eggs from Julia Lite hens, brown-shelled eggs, and iodine-enriched eggs from Boris Brown hens) were purchased from markets in Kochi City, Japan, and the amounts of L-PGDS in them were determined by ICT-EIA. The amounts of L-PGDS per hen egg white were: brown-shelled eggs, 1,179.3±214.3 μg/egg; iodine-enriched eggs, 607.7±126.1 μg/egg; and white-shelled eggs, 350.0±74.1 μg/egg. These results show that the amount of L-PGDS in hen eggs varies depending on the hen lineage; it could also be affected to some extent by other factors, such as feeds and breeding environment.