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The role of N-glycosylation in kiwi allergy.

Garrido-Arandia M, Murua-García A, Palacin A, Tordesillas L, Gómez-Casado C, Blanca-Lopez N, Ramos T, Canto G, Blanco C, Cuesta-Herranz J, Sánchez-Monge R, Pacios LF, Díaz Perales A - Food Sci Nutr (2014)

Bottom Line: The physical, biochemical, and immunological characteristics of plant allergens have been widely studied, but no definite conclusion has been reached about what actually makes a protein an allergen.With this aim, we evaluated and compared the allergenic activity of the protein fraction and the N-glycan fraction of the thaumatin-like protein and the main kiwi allergen, Act d 2.Related to this, the production of cytokines such as IL6 and IL10 was increased by the incubation of dendritic cells with sugar moiety.

View Article: PubMed Central - PubMed

Affiliation: Centre for Plant Biotechnology and Genomics U.P.M. - I.N.I.A., Campus de Montegancedo Pozuelo de Alarcón, Madrid, Spain.

ABSTRACT
The physical, biochemical, and immunological characteristics of plant allergens have been widely studied, but no definite conclusion has been reached about what actually makes a protein an allergen. In this sense, N-glycosylation is an exclusive characteristic of plant allergens not present in mammals and it could be implied in allergenic sensitization. With this aim, we evaluated and compared the allergenic activity of the protein fraction and the N-glycan fraction of the thaumatin-like protein and the main kiwi allergen, Act d 2. The natural allergen, Act d 2, was deglycosylated by trifluoromethanesulfonic acid treatment; the N-glycan fraction was obtained by extended treatment with proteinase K. N-glycan- and protein- fractions were recognized by specific IgE of kiwi-allergic patients. By contrast, the sugar moiety showed a reduced capacity to activate basophils and T cells, but not dendritic cells derived from patients' monocytes. Related to this, the production of cytokines such as IL6 and IL10 was increased by the incubation of dendritic cells with sugar moiety. Thus, the sugar moiety plays a significant role in sensitization, inducing the activation of antigen-presenting cells, but it is the protein fraction that is responsible for the allergic reactions.

No MeSH data available.


Related in: MedlinePlus

(A) Specific IgE levels in optical density units of kiwi extract, Act d 2, dAct d 2 and N-glycan fraction. Individual sera from 24 kiwi-sensitized patients were used. (B) Basophil activation tests in kiwi-allergic patients. The stimulation index (SI) is shown, calculated as% treated basophils/% untreated basophils. Responses involving 15% activated basophils and SI 2 were considered positive. (C) Activation of peripheral blood mononuclear cells (PBMCs). Positive SI responses (SI 2) of PBMCs from kiwi-allergic patients to Act d 2, dAct d 2, and N-gly is represented.
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fig03: (A) Specific IgE levels in optical density units of kiwi extract, Act d 2, dAct d 2 and N-glycan fraction. Individual sera from 24 kiwi-sensitized patients were used. (B) Basophil activation tests in kiwi-allergic patients. The stimulation index (SI) is shown, calculated as% treated basophils/% untreated basophils. Responses involving 15% activated basophils and SI 2 were considered positive. (C) Activation of peripheral blood mononuclear cells (PBMCs). Positive SI responses (SI 2) of PBMCs from kiwi-allergic patients to Act d 2, dAct d 2, and N-gly is represented.

Mentions: Act d 2, dAct d 2, and the N-glycan fraction (N-gly) were used as a solid phase to determine the specific IgE levels of single sera from 24 kiwi-allergic patients. Positive response to naïve allergen (Act d 2) was observed in all patients, while 16 of them (66.7%) recognized both fractions separately (Fig. 3A). Bromelain (Ana c 2)—a glycoprotein used as CCD control—gave a positive response in only four (17%) of these patients (data not shown).


The role of N-glycosylation in kiwi allergy.

Garrido-Arandia M, Murua-García A, Palacin A, Tordesillas L, Gómez-Casado C, Blanca-Lopez N, Ramos T, Canto G, Blanco C, Cuesta-Herranz J, Sánchez-Monge R, Pacios LF, Díaz Perales A - Food Sci Nutr (2014)

(A) Specific IgE levels in optical density units of kiwi extract, Act d 2, dAct d 2 and N-glycan fraction. Individual sera from 24 kiwi-sensitized patients were used. (B) Basophil activation tests in kiwi-allergic patients. The stimulation index (SI) is shown, calculated as% treated basophils/% untreated basophils. Responses involving 15% activated basophils and SI 2 were considered positive. (C) Activation of peripheral blood mononuclear cells (PBMCs). Positive SI responses (SI 2) of PBMCs from kiwi-allergic patients to Act d 2, dAct d 2, and N-gly is represented.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048612&req=5

fig03: (A) Specific IgE levels in optical density units of kiwi extract, Act d 2, dAct d 2 and N-glycan fraction. Individual sera from 24 kiwi-sensitized patients were used. (B) Basophil activation tests in kiwi-allergic patients. The stimulation index (SI) is shown, calculated as% treated basophils/% untreated basophils. Responses involving 15% activated basophils and SI 2 were considered positive. (C) Activation of peripheral blood mononuclear cells (PBMCs). Positive SI responses (SI 2) of PBMCs from kiwi-allergic patients to Act d 2, dAct d 2, and N-gly is represented.
Mentions: Act d 2, dAct d 2, and the N-glycan fraction (N-gly) were used as a solid phase to determine the specific IgE levels of single sera from 24 kiwi-allergic patients. Positive response to naïve allergen (Act d 2) was observed in all patients, while 16 of them (66.7%) recognized both fractions separately (Fig. 3A). Bromelain (Ana c 2)—a glycoprotein used as CCD control—gave a positive response in only four (17%) of these patients (data not shown).

Bottom Line: The physical, biochemical, and immunological characteristics of plant allergens have been widely studied, but no definite conclusion has been reached about what actually makes a protein an allergen.With this aim, we evaluated and compared the allergenic activity of the protein fraction and the N-glycan fraction of the thaumatin-like protein and the main kiwi allergen, Act d 2.Related to this, the production of cytokines such as IL6 and IL10 was increased by the incubation of dendritic cells with sugar moiety.

View Article: PubMed Central - PubMed

Affiliation: Centre for Plant Biotechnology and Genomics U.P.M. - I.N.I.A., Campus de Montegancedo Pozuelo de Alarcón, Madrid, Spain.

ABSTRACT
The physical, biochemical, and immunological characteristics of plant allergens have been widely studied, but no definite conclusion has been reached about what actually makes a protein an allergen. In this sense, N-glycosylation is an exclusive characteristic of plant allergens not present in mammals and it could be implied in allergenic sensitization. With this aim, we evaluated and compared the allergenic activity of the protein fraction and the N-glycan fraction of the thaumatin-like protein and the main kiwi allergen, Act d 2. The natural allergen, Act d 2, was deglycosylated by trifluoromethanesulfonic acid treatment; the N-glycan fraction was obtained by extended treatment with proteinase K. N-glycan- and protein- fractions were recognized by specific IgE of kiwi-allergic patients. By contrast, the sugar moiety showed a reduced capacity to activate basophils and T cells, but not dendritic cells derived from patients' monocytes. Related to this, the production of cytokines such as IL6 and IL10 was increased by the incubation of dendritic cells with sugar moiety. Thus, the sugar moiety plays a significant role in sensitization, inducing the activation of antigen-presenting cells, but it is the protein fraction that is responsible for the allergic reactions.

No MeSH data available.


Related in: MedlinePlus