The newly formed MHC II-Ii complex exits the TGN and ultimately is delivered to late-endosome/lysosome compartments. A proportion of the nonameric complex traffics directly from the TGN to these compartments, while a substantial population follow the indirect pathway involving transport from the TGN to the plasma membrane, followed by endocytic delivery to early endosomes, late endosomes, and finally lysosomes (McCormick et al. 2005). Transport carrier vesicles may traffic the cargo MHC II-Ii complex from the TGN to the plasma membrane.