Veiled cells--"dendritic cells" of the peripheral lymph.

The veiled cells (VC) of afferent lymph can be classified with dendritic cells (DC) of tissues on the basis of morphology, surface markers, cytochemical staining and function. VC form a population of cells, shown to carry antigens, in transit from the peripheral tissues to the paracortical areas of the lymph nodes. They can stimulate lymphocyte proliferation with antigens in vitro when added as less than 1% of the mononuclear cell population. They may initiate responses to foreign antigens such as keyhole limpet haemocyanin and 1-fluoro-2,4-dinitrobenzene (DNFB) and to alloantigen in the mixed leucocyte reaction or during grafting. VC may also be involved in antigen presentation in inflammatory and autoimmune diseases.