Buckwheat allergy has been recognized as a common food allergy with increasing consumption of the crop. It is considered to be one of the leading causes of food anaphylaxis. In this study, we prepared the hypoallergenic buckwheat proteins using the naturally occurring Maillard-type glycosylation and investigated their effect on immune response of spleen cells. Whole buckwheat proteins (WBP) was glycosylated with 40 kDa dextrans (DX40) under the controlled dry-heating at 65°C and RH79 for 2 weeks. The resulting conjugates of WBP and DX40 (WBP-DX40) decreased the ratio of MHC class II/CD86 double-positive cells compared to control. WBP-DX40 further decreased the levels of Th2-related cytokines such as IL-4 and IL-10 in the spleen cells and did not affect the secretion level of IFN-γ. These results suggest that the attachment of DX40 to WBP induces the suppression of Th2- immune response against buckwheat proteins.