Human thymus contains 2 distinct dendritic cell populations

• Published in: Blood Vol. 97; no. 6; pp. 1733 - 1741
• Main Authors: Vandenabeele, Stéphane, Hochrein, Hubertus, Mavaddat, Nasim, Winkel, Ken, Shortman, Ken
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 15.03.2001; The Americain Society of Hematology
• Subjects: Analysis of the immune response. Humoral and cellular immunity; Animals; Biological and medical sciences; CD40 Ligand - pharmacology; CD8-Positive T-Lymphocytes - cytology; CD8-Positive T-Lymphocytes - immunology; Cell Culture Techniques; Cell Separation; Dendritic Cells - cytology; Dendritic Cells - immunology; Dendritic Cells - metabolism; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunoassay; Immunobiology; Immunophenotyping; Interleukin-12 - metabolism; Macrophage-1 Antigen - genetics; Macrophage-1 Antigen - metabolism; Mice; Organs and cells involved in the immune response; RNA, Messenger - metabolism; Thymus Gland - cytology; Dendritic cell; Antigen presentation; Thymus gland; Cell population; Immunophenotype; Biological marker; Accessory cell
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V97.6.1733

In this study, 2 distinct populations of mature dendritic cells (DCs) were identified in the human thymus. The major population is CD11b−, CD11c+, and CD45ROlowand does not express myeloid-related markers. It displays all the characteristics of mature DCs with a typical dendritic morphology, high surface levels of HLA-DR, CD40, CD83, and CD86, and expression of DC–lysosome-associated membrane glycoprotein messenger RNA (mRNA). In addition, CD11b− thymic DCs do not express macrophage inflammatory protein-1α (MIP-1α) mRNA, but express thymus-expressed chemokine (TECK) mRNA and are able to secrete bioactive interleukin 12 (IL-12) upon stimulation. In contrast, the minor and variable thymic DC population is CD11b+, CD11chigh, and CD45ROhigh and comprises CD83+CD14− mature and CD83−CD14+ immature DCs. It expresses macrophage-colony stimulating factor receptor, MIP-1α mRNA and high amounts of decysin mRNA after CD40 activation, but does not express TECK and is a weak bioactive IL-12 producer. Also identified were the IL-3Rαhigh plasmacytoid cells, which are present in the thymic cortex and medulla. Upon culture with IL-3, granulocyte/macrophage–colony stimulating factor, and CD40 ligand, the plasmacytoid cells can adopt a phenotype resembling that of freshly isolated CD11b− thymic DCs. However, these plasmacytoid-derived DCs fail to secrete bioactive IL-12; therefore, conclusions cannot be made about a direct relation between thymic plasmacytoid cells and CD11b− DCs. Whereas CD11b+ thymic DCs appear to be related to tonsillar germinal-center DCs, the major CD11b− IL-12–secreting human thymus DC population has similarities to mouse CD11b− CD8+ DCs.