Fig 8. Proposed model of S. mansoni–driven Th2 polarization.

S. mansoni egg antigens, but not ω-1, interact with Dectin-1 and Dectin-2 expressed by DCs to promote 2 intracellular pathways in moDCs in an Syk-dependent manner: ERK-cPLA₂-COX and ROS activity that culminate in PGE₂ and PGE₂ isomer synthesis, respectively. Both PGE₂ and its isomers can then bind to EP2 and EP4 in an autocrine loop to trigger OX40L expression, which endows the DCs with the capacity to prime a Th2 response. ω-1, omega-1; COX, cyclooxygenase; cPLA₂, cytosolic phospholipase A₂; DC, dendritic cell; EP2, prostaglandin E₂ receptor 2; ERK, extracellular signal-regulated kinase; moDC, monocyte-derived DC; OX40L, OX40 ligand; PGE₂, prostaglandin E₂; ROS, reactive oxygen species; Syk, spleen tyrosine kinase; Th2, T helper 2.