STRUCTURAL PECULIARITIES OF VASCULAR DENDRITIC CELL TUBULOVESICULAR SYSTEM IN HUMAN ATHEROSCLEROTIC AORTA

The principal function of vascular dendritic cells has been suggested to be antigen processing/presentation but how this might occur is not clear. To find out whether the organisation of vascular dendritic cell s might allow them to internalise antigens, we used electron microscop y to examine their fine cytoarchitectonics. Tubular and vesicular stru ctures were observed to form continuous nets through which extracellul ar molecules might gain access to lysosomes. This suggests that vascul ar dendritic cells might be able to degrade antigens using the same me chanisms as occur in macrophages. We also speculate that antigen proce ssing might be different between type I vascular dendritic cells which possess a hypertrophied tubulovesicular system and type Il vascular d endritic cells where the tubulovesicular system is less prominent. The present work indicates that the tubulovesicular system is functionall y associated with the extracellular space. This connection with the ex tracellular space through the system of cisterns and vesicles can allo w the transport of different substances entering the cistern nets.