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3. Pollen Allergy and Glycan |
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● Cedar hay fever and glycan antigen The increase in hay fever is suggested to be relate to stress and traffic and can be said as one of the modern diseases. Among Japanese pollen allergies, the population of cedar hay fever is the most, and as main pollen allergens scattered from Japanese cedar (Cryptomeria japonica), Cryj I, Cryj II were already identified. Cryj I is glycoprotein that includes about 6-8% of sugar. Because there is a lot of glycoprotein in plant allergen, it is doubted all over the world that glycan is the cause of allergy. At first we refined analyzed Cryj I from cedar pollen and analyzed its glycan structure in a small amount. The main glycan of Cryj I is two-chains compound type glycan that includes core structure which is characteristic of plant glycoprotein and side chain. We also found out by using ELISA method that IgE which is made by injecting Cryj I into a rabbit recognizes glycan and bonds with it. These kinds of antibodies cross-react to various other plant glycoproteins that have common glycan parts. However, IgE included in serum of allergic patients does not react to Cryj I glycan, and we found out that Cryj I glycan is not the main epitope of IgE in allergic patients 1). Different from glycan parts of honey bee poison, phospholipase A2, and olive pollen allergen that were suggested as IgE epitope, in Cryj I, the main epitope is not glycan but probably peptide depended on conformation. However, other kinds of hay fevers it has been reported that there are a few patients who have IgE reacting to glycan. About antigen of allergen glycan, there thought to be individual, regional and racial differences, and we need to get a lot more data about it. We are also interested in the structure of glycan epitope that bonds with IgE, distribution in natural and food allergens and the mechanism that produces anti-glycan antibody 2, 3).
1)
Ogawa H., et al. (1996)
Glycoconj. J.,
13
, 555-566
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