ANTIGEN-BEARING LANGERHANS CELLS IN SKIN, DERMAL LYMPHATICS AND IN LYMPH-NODES

Ferritin-challenged skin sites and draining lymph nodes were studied in normal guinea pigs and in guinea pigs passively sensitized to ferritin or [horseradish] peroxidase by lymphoid cell transfer to ascertain whether Langerhans cells can bind antigen in skin and carry it to lymph nodes. After intradermal challenge with amounts of ferritin as small at 5 .mu.g, ferritin-containing Langerhans cells were seen by EM in the marginal sinus and cortex of draining lymph nodes in ferritin-sensitized animals and, to an apparently lesser degree, in control animals. Lymph nodes from unchallenged normal guinea pigs contained rare Langerhans cells, none of which had ferritin. Langerhans cells may apparently pick up antigen in skin and from there circulate to draining lymph nodes, thus carrying out a function analogous to macrophages. In this way they may exhibit antigen to lymphocytes in skin and in lymph nodes.