IgE and IgG antibody response to natural and recombinant Pen a 1 measured by ELISA and mediator release assay

To assess mouse reactivity to the major shrimp allergen, nPen a 1 and rPen a 1 were used to analyze murine IgG and IgE antibody responses by ELISA, and mediator release in rat basophilic leukemia (RBL) cells. C3H/HeJ mice were orally immunized with shrimp extract, nPen a 1, and rPen a 1 (0.1–10ug) using cholera toxin as adjuvant. IgG and IgE responses were quantified by ELISA. RBL cells were sensitized with IgE-containing mouse sera; mediator release was measured after challenging the cells with Pen a 1. Higher doses of shrimp extract, nPen a 1, and rPen a 1 stimulated greater IgG and IgE antibody production. rPen a 1 induced the highest antibody response followed by nPen a 1 and shrimp extract, respectively. Comparison of 10ug rPen a 1 to 10ug shrimp extract demonstrated a two-fold greater IgG response and a three-fold greater IgE response. However, 0.1ug of rPen a 1 induced a higher IgE response than 1.0ug rPen a 1. Serum from Pen a 1 immunized mice also reacted to crawfish, snowcrab, and lobster extracts. In the RBL assay, Pen a 1 showed comparable allergenic potency as shrimp; this is similar to shrimp allergy in humans. This study suggests that rPen a 1 yields an antibody response superior to both shrimp extract and nPen a 1 in mice. Pen a 1 accounts for most of the allergenic potency of shrimp. The data suggests this model is a suitable tool to study novel immunotherapy treatments for shrimp allergy.