Characterization of Human CD34⁺ Derived Dendritic/Langerhans Cells (D-Lc)

Abstract

Dendritic cells (DC) are professional antigen presenting cells which are found in all lymphoidand non lymphoid organs. The various DC are thought to represent different steps ofmaturation of the same lineage which function as sentinel of the immune system. In theperiphery, DC such as Langerhans cells (Lc) capture the antigen, then migrate via thelymphatics and home to the T cell rich area of lymph nodes where they are calledinterdigitating cells (IDC). There, they present processed antigen to naive T cells and generatean antigen specific primary T cell response (1). DC are from bone marrow origin (2) and weand others have shown, in human, the cooperation of GM-CSF and TNFα in the generationfrom hematopoietic progenitor cells (HPC) of high numbers of DC related to Lc (3, 4, 5) Inthe present study we show that i) These in vitro generated dendritic/ Langerhans cells (D-Lc)are very potent in priming naive T cells and in capturing, processing and presenting solubleantigen to antigen-specific T cell clones, ii) B70/B7-2 is identical to CD86 and is the majorfunctionnal ligand for CD28. iii) Two subsets of D-Lc precursors were identified, whichgenerate either Birbeck granules (BG) positive Lc or BG^- CDla⁺ DC.