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Identification of mature and immature human thymic dendritic cells that differentially express HLA‐DR and interleukin‐3 receptor in vivo
Author(s) -
Schmitt Christian,
Fohrer Hélène,
Beaudet Sylvie,
Palmer Pierre,
Alpha MarieJosé,
Canque Bruno,
Gluckman Jean Claude,
Dalloul Ali H.
Publication year - 2000
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.68.6.836
Subject(s) - biology , myeloid , immunology , cd40 , cd38 , cytokine , cd34 , microbiology and biotechnology , stem cell , cytotoxic t cell , in vitro , biochemistry
We have previously shown that thymic CD34 + cells have a very limited myeloid differentiation capacity and differentiate in vitro mostly into CD1a + ‐derived but not CD14 + ‐derived dendritic cells (DC). Herein we characterized the human neonatal thymic DC extracted from the organ in relationship with the DC generated from CD34 + cells in situ . We show that in vivo thymic DC express E cadherin, CLA, CD4, CD38, CD40, CD44, and granulocyte‐macrophage colony‐stimulating factor‐R (GM‐CSF‐R; CD116) but no CD1a. According to their morphology, functions, and surface staining they could be separated into two distinct subpopulations: mature HLA‐DR hi , mostly interleukin‐3‐R (CD123)‐negative cells, associated with thymocytes, some apoptotic, and expressed myeloid and activation markers but no lymphoid markers. In contrast, immature HLA‐DR + CD123 hi CD36 + cells with monocytoid morphology lacked activation and myeloid antigens but expressed lymphoid antigens. The latter express pTα mRNA, which is also found in CD34 + thymocytes and in blood CD123 hi DC further linking this subset to lymphoid DC. However, the DC generated from CD34 + thymic progenitors under standard conditions were pTα‐negative. Thymic lymphoid DC showed similar phenotype and cytokine production profile as blood/tonsillar lymphoid DC but responded to GM‐CSF, and at variance with them produced no or little type I interferon upon infection with viruses and did not induce a strict polarization of naive T cells into TH2 cells. Their function in the thymus remains therefore to be elucidated.