ABSTRACT
Epidermal Langerhans' cell (LC) migration to the regional lymph node and beyond into central lymph was examined in sheep following topical application of the complete chemical carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) or the contact sensitizing antigen 2,4,6-trinitrochlorobenzene (TNCB). This was facilitated by cannulating previously constructed pseudoafferent lymphatic vessels draining the skin treated with these agents or alternatively, the efferent lymphatic vessel of the regional lymph node. Application of DMBA resulted in a biphasic increase in LC migration. There was an initial increase in LC migration at 25 h with the maximum response (3.6 x 10(7) LC/h) occurring approximately 5 days after DMBA treatment. In contrast, the contact sensitizing antigen TNCB caused enhanced LC migration within minutes of the application of antigen (3.3 x 10(6) LC/h) and peak migration at 8-12 h. Examination of efferent lymph cells from the regional lymph node after DMBA treatment showed uncharacteristically large numbers of LC traversing the lymph node. These LC migration patterns suggest different mechanisms may trigger the migration of LC from skin after the application of DMBA to those associated with the normal processes of antigen presentation.
