Abstract: The present study was undertaken to discover the effect of casein glycomacropeptide (CGMP) on maturation of in vitro cultured mouse bone marrow-derived dendritic cells and gain a preliminary understanding of the immunoregulatory functions of CGMP as a functional food ingredient. Bone marrow-derived dendritic cells (BM-DCs) from 6－8 week-old male C57BL/6 mice were isolated, cultured and differentiated in the presence of both rmIL-4 and rmGM-CSF. On day 6 of the culture process, three doses of CGMP (0, 0.1, 1.0μg/mL and 10μg/mL), RPMI 1640 complete medium (blank control) and LPS (positive blank) were added respectively and the BM-DCs were cultured for another 2 days, harvested, labeled with three fluorescence and examined for the surface markers CD11c, CD80, CD86, and MHC-Ⅱ by flow cytometry. Meanwhile, the harvested BM-DCs and T lymphocytes were co-cultured for 96 h before Cell Counting Kit-8 (CCK-8) examination of T lymphocyte proliferation resulting from mixed lymphocyte reaction (MLP). The results showed that all three doses of CGMP could promote the maturation of BM-DCs. All the maturation markers of dendritic cells reached their maximum at the dose of 1 μg/mL. Among the markers, MHC-Ⅱ, which plays a significant role in antigen presentation by BM-DCs, was promoted most. Co-culture of BM-DCs and T lymphocytes showed that BM-DCs treated with CGMP promoted the proliferation of T lymphocytes. T lymphocytes BM-DCs showed maximum proliferation when the initial ratio of BM-DCs to T lymphocytes was 1:10.

Key words: casein glycomacropeptide(CGMP), dendritic cells(DCs), flow cytomety, antigen presentation, mixed lymphocyte reaction (MLP)