[#1994-04] Enhancement of cytokine production by macrophages stimulated with (1->3)-beta-D-glucan, grifolan (GRN), isolated from Grifola frondosa, Y. Adachi et al.

Enhancement of cytokine production by macrophages stimulated with (1->3)-beta-D-glucan, grifolan (GRN), isolated from Grifola frondosa

Adachi Y, Okazaki M, Ohno N, Yadomae T.

Laboratory of Immunopharmacology of Microbial Products, Tokyo University of Pharmacy and Life Science

The ability of grifolan (GRN, maitake derived ), a purified fungal (1->3)-β-D-glucan, to induce various cytokines from macrophages was examined in vitro. Interleukin-6 (IL-6) activity in supernatants from the culture of macrophage cell line, RAW264.7 was dependent on increasing doses of GRN. The level of IL-6 induced with 500 μg/ml of GRN was comparable to that induced with lipopolysaccharide (LPS) 10 micrograms/ml. Enhancement of the mRNA level of IL-6 by treatment with GRN was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). The effect of GRN on production of IL-6 was also observed using peritoneal macrophages from C3H/HeJ mice which did not respond to endotoxins. This data suggested that the ability of GRN to activate IL-6 production of macrophages is not due to contamination of endotoxins in the preparation. Enhanced production of cytokine by GRN was observed not only with IL-6, but also with interleukin-1 (IL-1) and tumor necrosis factor α (TNFα). In the production of TNFα, GRN was more effective than LPS used in this study. Other soluble or gel-forming(1->3)-β-D-glucans from various sources did not enhance the production of such cytokines although they are structurally similar to GRN. The above results indicate that GRN is a novel macrophage activator which augments cytokine production without dependence on endotoxins.