ISOLATION AND CHARACTERIZATION OF THE INTRACELLULAR MHC CLASS-II COMPARTMENT

An intracellular compartment has been isolated to which MHC class II m olecules are transported on their way to the plasma membrane. They arr ive with an associated invariant chain which is then proteolytically p rocessed while MHC class II molecules acquire antigenic peptide. These loaded class II molecules then leave the compartment devoid of invari ant chain and bound for the plasma membrane. This compartment represen ts a new stage in the endocytic/lysosomal pathway.