PRODUCTIONS OF INTERFERON-GAMMA AND NITRITE ARE INDUCED IN MOUSE SPLENIC CELLS BY A HETEROGLYCAN-PROTEIN FRACTION FROM CULTURE-MEDIUM OF LENTINUS-EDODES MYCELIA

A xylose-rich heteroglycan-protein fraction (LAP1) was prepared from a solid culture medium in which Lentinus edodes mycelia were growing ac tively. Mouse splenic cells (SPs) were incubated with [H-3]TdR in the presence of LAP1. The incubated SPs were fractionated into plastic adh erent splenic cells (ADs), nylon-column effluent splenic cells (NEs) a nd sig-expressed splenic cells (SIs), which are rich in Mac-1(+), Thy- 1.2(+) and Ly-5(+) cells, respectively. The incorporation of [3H]TdR i n response to LAP1 was enhanced in each of the fractionated cell popul ations. Northern or dot blot hy bridization showed that productions of IFN-gamma and its receptor mRNAs are induced predominantly in NEs. In another experiment, SPs were fractionated into ADs, NEs and SIs. Then , NE-AD, SI-AD and NE-SI mixtures were prepared and incubated in the s ame manner. A significant incorporation of [H-3]TdR was shown only in the NE-AD mixture. The enzyme-linked immunosorbent assay showed that I FN-gamma production in response to LAP1 is induced in SPs or in the NE -AD mixture, but not in NEs alone. The level of the production was abo ut 5 times higher in the mixture than in SPs after a 72 h incubation. Moreover, LAP 1 was capable of inducing NO2- production in SPs. Thus, the present studies imply that this heteroglycan-protein fraction stim ulates productions of IFN-gamma and nitrite in mouse splenic cells, au gmenting antitumor immune response(s).