A potent naturally occurring low-molecular weight blastogenic inhibitory factor from edible black tree fungus.

Crude dialyzable extracts of Auricularia polytricha (black tree fungus) when added to lymphoprep-isolated blood mononuclear cells (PBL) stimulated with mitogens (PHA and PWM) showed significant inhibition of 3H-thymidine (3H-TdR) incorporation in vitro. Similar extracts of Agaricus biporus and Cortinellus shiitake demonstrated essentially no suppression of 3H-TdR uptake by PBL cells stimulated with PHA or PWM. A 50 micrograms/well (200 microliter) concentration of A. polytricha reduced 3H-TdR uptake of PHA stimulated PBL cells from different donors by 65.4 to 99.8% and similarly reduced 3H-TdR uptake of PWM stimulated PBL cells by 89.6 to 99.9%. Viability examination of PBL cells in RPMI medium with A. polytricha extract alone, mitogens alone, and mixtures of mitogens and extract for 72 hr at 37 degrees C showed per cent survivals as follows: medium alone, 93%; PWM, 91%; PHA, 77%; BTF extract (200 micrograms/ml), 57%; PWM + BTF extract, 47%, and PHA + BTF extract, 39%. Data presented show that Auricularia polytricha contained a low dalton potent blastogenic inhibitory factor(s).