Among the other cytokines analyzed, no significant change was detected in the levels of IL-2, IL-6, IL-10, and TNF-α (Fig. 4c). However, significant decrease was seen in the level of IL-1α and IL-1β at day 3 and 5, respectively. Level of IL-1α remained downregulated until day 5 indicating inverse correlation of its expression with IFN-β. These results are consistent with recent studies suggesting a negative regulatory role of IFN-β in the maturation of IL-1α/β41,42. Type II interferon (IFN-γ) produced primarily by activated T cells was not detected in all cases. Taken together, our results show that unlike LPS, peroral administration of 2,000-kDa γ-PGA selectively induces IFN-β but not inflammatory cytokines.