Roles of carbohydrates on Cry j 1, the major allergen of Japanese cedar pollen, in specific T-cell responses.

BACKGROUND

Carbohydrates expressed on allergens are known to be important for allergenicity. However, little is known about whether the carbohydrates drive the T(H)2 response.

OBJECTIVE

We sought to determine a role for carbohydrates expressed on Cry j 1, which is the major allergen of Cryptomeria japonica pollen and causes the most prevalent pollinosis in Japan, in in vitro cellular responses.

METHODS

Carbohydrates on Cry j 1 were destroyed by periodate-oxidation under mild conditions. Proliferative responses and cytokine productions against native, periodate-treated, and mock-treated Cry j 1 were compared in peripheral blood mononuclear cells, Cry j 1-specific T-cell lines, and clones from patients with Japanese cedar pollinosis.

RESULTS

We found that peripheral blood mononuclear cells from patients with Japanese cedar pollinosis displayed a significant decrease in proliferation and IL-5 production in response to periodate-treated Cry j 1 in comparison with native and mock-treated Cry j 1. Decreased proliferative responses against periodate-treated Cry j 1 were also seen in polyclonal T-cell lines, and the responses showed a heterogeneity. In addition, Cry j 1-specific CD4+ T-cell clones also displayed a significant decrease in proliferation and IL-4 and IL-5 production-but not IFN-gamma production-in comparison with the control antigens. However, most of the clones showed decreased but positive proliferative responses against periodate-treated Cry j 1. Blockade of the mannose receptor had no effect on cellular responses.

CONCLUSIONS

The results suggest that carbohydrates on Cry j 1 play a major role in promoting Cry j 1-specific T(H)2 response in vitro, though they are not major targets as T-cell epitopes.