Figure 7. Model of ABB and non-ABB component trafficking.

Cell surface ABB complexes (the Fc of anti-gD_hFc bound to gE-gI and the Fabs bound to gD) are endocytosed into early endosomes (EE) and sorting endosomes (SE). Upon acidification, the Fc region of anti-gD_hFc dissociates from gE-gI but the Fabs remain bound to gD. The IgG-gD complex then enters the lysosomal pathway (Lys) to be degraded. Intracellular trafficking of compartments containing ABB components depends upon intact microtubules (thin straws adjacent to intracellular vesicles). Free gE-gI could be trafficked via a retrograde pathway to the Golgi/ER network and recycling endosomes (RE) before recycling back to the cell surface. IgG_hFc bound to gE-gI traffics similarly, but does not recruit cell surface gD into ABB complexes. Anti-gD_mFc remains bound to gD at the cell surface.