Relationship between dendritic cells and the D-fraction-induced Th-1 dominant response in BALB/c tumor-bearing mice.

Dendritic cells (DCs) are known to not only induce the activation of T cells, but are also associated with the differentiation of T cells. The D-fraction, a beta-glucan extracted from maitake (Grifola frondosa) which expresses anti-tumor effects by establishing a helper (Th)-1 dominance in BALB/c mice, enhanced IL-12p70 production by DCs, when the ratio of CD8alpha(+) DCs to CD8alpha(-) DCs increased. In addition, examination of the tumor rejection effect of D-fraction-stimulated DCs loaded with tumor antigen revealed that tumor growth is inhibited completely by activating CD4(+) T cells and CD8(+) T cells.