Arabinoxylan rice bran (MGN-3/Biobran) (also known as Lentin Plus 1000) has been shown to be a potent biological response modifier (BRM) that activates different arms of the immune system, including dendritic cells (DCs), which prime CD4+ helper T-cell responses.

The present study explores the ability of MGN-3-activated DCs to prime CD8+ T cells and examines the mechanisms underlying its effect. Human monocyte-derived DCs were treated with MGN-3 (20 and 40 µg/ml). Results indicate that treatment with MGN-3 caused DCs to prime higher granzyme B-expressing CD8+ T cells. Tumor lysate-pulsed MGN-3 DC also increased tumor cell killing compared to DC-stimulated CD8+ T cells.

This was associated with: i) increased expression of DEC-205 in MGN-3-activated DCs in a dose—dependent manner; and ii) MGN-3 induced significant production of Type III interferon, IL29, but not Type I IFNs on and B. These results suggest that MGN-3 is a potent natural adjuvant that efficiently activates DCs and may therefore be useful for mounting an efficient immune response against infections and cancer.