Induction of cytotoxic factor in mice by lignified materials combined with OK-432 (Picibanil).

Intravenous administration of pine cone lignin-related substance (Fr. VI) significantly stimulated OK-432-elicited cytotoxic factor (CF) production in ICR mouse serum. The level of CF elicited after OK-432 administration peaked after 2 h and declined to basal level within 6 h. The CF productibility depended greatly on both dose and the interval between the administration of the Fr. VI and OK-432. Most natural and synthetic lignins, their degradation products, and polysaccharides, including pine cone hemicellulose fractions, had much weaker CF-inducing (priming) activity. When Fr. VI was treated with NaCl02 to decompose the lignin portion, the priming activity was significantly reduced. The data suggest that the potent priming activity of Fr. VI might de a result of some conjugation between the lignin portion and other components including polysaccharides.