Immunogold labelling on ultra-thin cryosection in electron microscopy. The left picture shows multilaminar MIICs in immature dendritic cells labelled for MHC class II molecules. The right picture shows a MIIC in maturing dendritic cells also labelled for MHC class II molecules. In addition of class II redistribution at the cell surface, maturation of dendritic cells induces morphological changes of MIICs: packaging of internal membranes and formation of tubules from the limiting membrane.The picture was awarded at the SCANDEM 2003 meeting.