The potent IgG4-inducing antigen in banana is a mannose-binding lectin, BanLec-I.

IgG4 antibodies to banana were found to occur far more frequently than expected. The most important antigen involved proved to be a lectin, BanLec-I. Because of the lectin nature of the antigen, it was important to establish the antibody nature of the lectin-IgG4 interaction and to exclude an interaction between the sugar-binding site of the lectin and glycosidic chains on IgG4.

Relationship between IgG1 and IgG4 antibodies to foods and the development of IgE antibodies to inhalant allergens. II. Increased levels of IgG antibodies to foods in children who subsequently develop IgE antibodies to inhalant allergens.

In the present investigation we have tested the hypothesis that children with a high IgG antibody response to foods have an increased risk of developing IgE antibodies to inhalant allergens. Sera from 106 children with an increased risk of developing IgE-mediated allergy were analysed. During the follow-up, in 54 of these children IgE antibodies to inhalant allergens appeared.

Relationship between IgG1 and IgG4 antibodies to foods and the development of IgE antibodies to inhalant allergens. I. Establishment of a scoring system for the overall food responsiveness and its application to 213 unselected children.

To obtain reference levels for subsequent investigations, we analysed the IgG1 and IgG4 antibody levels to common foods in the sera of 213 unselected children (age 3 months to 14 years). The children were clustered into five age groups and tested on a broad screening panel of common foods. We used the IgG1 and IgG4 RAST with Sepharose-coupled antigens: cows' milk, hens' egg white, banana, legumes (a mixture of soybean and peanut), grains (a mixture of wheat and rice), potato, orange and pork.

Isolation and characterization of BanLec-I, a mannoside-binding lectin from Musa paradisiac (banana).

A lectin (BanLec-I) from banana (Musa paradisiac) with a binding specificity for oligomannosidic glycans of size classes higher than (Man)6GlcNAc was isolated and purified by affinity chromatography on a Sephadex G-75 column. It did not agglutinate untreated human or sheep erythrocytes, but it did agglutinate rabbit erythrocytes. BanLec-I stimulated T-cell proliferation.

Cross-reactivity of IgE antibodies to caddis fly with arthropoda and mollusca.

We investigated the possibility that subjects with IgE antibodies to an inhalant insect allergen, such as caddis fly, might also have antibodies to cross-reacting carbohydrate determinants (CCDs). IgE antibodies to cross-reacting allergens in caddis flies, mussels, oysters, shrimps, crabs, honeybee, and yellow jacket venoms were determined by RAST, RAST inhibition, and immunoblot studies with sera from three different sources: (1) sera of patients with well-defined inhalant atopy to caddis fly, (2) sera with IgE anti-CCD antibodies from subjects without known exposure to caddis fly, and (3) hyperimmune antisera with IgG anti-CCD antibodies raised as a result of immunization of rabbits with grass-pollen extract, buckwheat glycoprotein, or with honeybee venom. Sera from groups 2 and 3 reacted with Sepharose-coupled caddis fly extract in a RAST-type assay and elicited virtually identical patterns on immunoblots of caddis fly extract separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whereas the sera from group 1 atopic patients did not react with CCD-rich material.