Acting mechanisms of Lentinan in human--I. Augmentation of DNA synthesis and immunoglobulin production of peripheral mononuclear cells.

The immunopotentiating activity and acting mechanisms of Lentinan were investigated in the human system, resulting in clarification of the following characteristics. (a) Augmentation of DNA synthesis of peripheral mononuclear cells (PMNC) occurred both in vitro and in vivo by adding or injecting Lentinan, for which the coexistence of T cells, B cells and adherent cells (mainly monocytes) was essential. (b) No additional mitogenic effect of Lentinan was observed when PMNC were incubated with both Lentinan and other mitogens. (c) In vitro production of immunoglobulin by PMNC induced with pokeweed mitogen was enhanced through the inhibition of suppressor T cell activity by Lentinan.