FIGURE 9.

CD86 Signaling Model. (Dotted arrows indicate proposed novel signaling events identified in the current study). CD86 engagement promotes the phosphorylation of IκBα via mechanisms regulated by Phb1/2 and the CD86 cytoplasmic domain allowing for the activation of NF-κB p50/p65. Concurrently, Phb1/2 alone promotes the CD86-induced PLCγ2 phosphorylation, allowing for subsequent PKCα/β_II activation and phosphorylation of p65. NF- κB p50/p65 is now poised to initiate Oct-2 transcription, which ultimately regulates 3′IgH- enhancer activity to increase the rate of IgG₁ transcription and the level of IgG₁ produced by a B cell.