Figure 6

A proposed scheme for IgG-bound platelet-induced regulatory response. In IgG-bound platelet-induced regulation, a reciprocal interaction of IgG-opsonized platelets with monocytes via FcγRs constitutes the main and sub pathways. The main pathway is mediated by platelet surface molecules such as integrins, and IgG and activating-type FcγRs including FcγRIIA/IIIA/I on monocytes. The sub pathway includes monocyte-surface molecules such as integrins, and IgG and FcγRIIA on platelets. We do not rule out the potential involvement of a platelet-surface molecule(s), which contributes to the interaction with monocytes. Since platelets are much smaller than monocytes, it is likely that these pathways for a monocyte will be attained with multiple platelets.