View article

Dendritic cells (DC) in nonlymphoid organs can internalize and process foreign antigens before migrating to secondary lymphoid tissues to initiate primary immune responses. However, there is little information on which stimuli promote migration of DC from the tissues. Systemic administration of lipopolysaccharide (LPS), which induces in vivo production of cytokines, led to a reduction in the numbers of major histocompatibility complex class II-positive (Ia+) leukocytes in mouse hearts and kidneys: > 95% of DC were depleted 1-3 d after injection of 50 micrograms LPS. Several lines of evidence indicated that this response was due to migration of DC rather than loss of Ia expression or cytotoxic effects. In skin of treated mice, the number of Ia+ epidermal Langerhans' cells (LC) was reduced, and "cords" of Ia+ leukocytes became evident in the dermis. The latter cells expressed little NLDC145 and may have originated …