Evaluation of basophil activation caused by transgenic rice seeds expressing whole T cell epitopes of the major Japanese cedar pollen allergens.

Abstract

BACKGROUND:

Japanese cedar (JC) pollinosis is a serious type I allergic disease in Japan. Although subcutaneous immunotherapy and sublingual immunotherapy have been applied to treat JC pollinosis, high doses of allergens may cause IgE-mediated allergic reactions. The transgenic rice seeds that contain genetically modified Cry j 1 and Cry j 2, the two major allergens of JC pollen, have been developed as candidates for oral immunotherapy. Although the antigens in the transgenic rice seeds (Tg-rice seeds) were engineered such that they decrease binding ability with IgE and they are of insufficient length to cross-link IgE on the surface of mast cells or basophils, the safety of Tg-rice seeds for patients with JC pollinosis was unclear.

METHODS:

To verify the safety of Tg-rice seeds in terms of allergies, we investigated the percentage of activated basophils induced by Tg-rice seed extract in the basophil activation test. Blood samples from 29 patients with JC pollinosis were collected. Tg-rice seed extract, non-transgenic wild-type rice seed extract, and Cry j 1 and Cry j 2 were mixed with the blood with reagents. The percentage of activated basophils was assessed by CD203c expression, a basophil activation marker.

RESULTS:

The percentage of activated basophils after the stimulation with Tg-rice seed extract was 4.5 ± 1.6% (mean ± SD) compared with 62.9 ± 20.2% after Cry j 1- and Cry j 2-stimulation (difference 58.4%, P < 0.001, 95% confidence interval 51.0-65.9%).

CONCLUSIONS:

The results will contribute to the safety of Tg-rice seeds in terms of allergies.

• Authors: Shinya Takaishi, Saburo Saito, Minori Kamada, Nobuyoshi Otori, Hiromi Kojima, Kenjiro Ozawa, Fumio Takaiwa
• Journal: Clinical and translational allergy (Clin Transl Allergy) Vol. 9 Pg. 11 ( 2019) ISSN: 2045-7022 [Print] England
• PMID: 30828418 (Publication Type: Journal Article)