Figure 2.

HMGB1 stimulates effector function from immune cells. In many instances, HMGB1’s function has been to subserve cell:cell interactions between lymphoid and myeloid cells. Its clearest definition has been with NK/macrophage or NK/DC interactions although suspected roles in B and T-cell activities are supported. What is unclear is whether these roles are cell type specific and whether HMGB1 might act in trans between a myeloid and lymphoid cell. “?” represents the state of uncertainty if HMGB1 plays a role in the setting of macrophage and NK cell interaction or HMGB1 is secreted from DCs to affect NK cell function.