Protein-rich fraction of Protaetia brevitarsis seulensis larvae induce maturation of dendritic cells and Th1-polarization: A promising adjuvant for anticancer therapy

The objective of this study was to investigate the potential anticancer immunostimulatory properties of a proteinrich fraction obtained from larvae of Protaetia brevitarsis seulensis (PBLP), a highly nutritious edible insect, in CT26 colon carcinoma-bearing mice. The most abundant essential amino acids (EAA) in PBLP were Val, Ile, and Leu, while the most abundant non-EAA were Pro, Glu, and Gly. PBLP increased the production of Th1-polarized cytokines and the phenotypic maturation of bone marrow-derived dendritic cells (BMDCs). PBLP-treated BMDCs stimulated naive CD4+ and CD8+ T cells to produce IFN-& gamma; and IL-2 but not IL-5. Significantly, dietary PBLP restored CD86 and MHC-I expression in splenic DCs, and also increased TNF-& alpha;+IL-2+IFN-& gamma;+CD107+ polyfunctional CD4+ and CD8+ T cells in the spleen, thereby inhibiting tumor growth in CT-26 tumor-bearing mice. Collectively, PBLP synchronizes DCs and T cells for anticancer immunity, suggesting that it could serve as a potential adjuvant or supplement for cancer treatment.