 After MHC class II complexes are synthesized and presented on APCs they are unable to be expressed on the cell surface indefinitely, due to the internalization of the plasma membrane by the APCs.In some cells, antigens bind to recycled MHC class II molecules while they are in the early endosomes, while other cells such as dendritic cells internalize antigens via receptor-mediated endocytosis and create MHC class II molecules plus peptide in the endosomal-lysosomal antigen processing compartment which is independent of the synthesis of new MHC class II complexes.These suggest that after the antigen is internalized, already existent MHC class II complexes on mature dendritic cells can be recycled and developed into new MHC class II molecules plus peptide.