CIIV, MIIC and other compartments for MHC class II loading.

Virtually every endocytic compartment has been claimed to be an MIIC, a site where class II molecules accumulate. Here, it is argued that the definition of MIIC is not accurate and often pointless. MIIC can better be used as a working title for a collection of late endocytic compartments that contain the goodies necessary for efficient peptide loading of class II molecules.