Isolation of the most immature population of murine fetal thymocytes that includes progenitors capable of generating T, B, and myeloid cells.

• DOI: 10.1084/jem.184.5.1901
• Publication Date: 2004-06-24T07:56:10Z
• Authors: N Hattori; H Kawamoto; Y Katsura
• Keywords: B-Lymphocytes; 0303 health sciences; Time Factors; T-Lymphocytes; Cell Cycle; Bone Marrow Cells; Cell Differentiation; Receptors, Fc; Thymus Gland; Flow Cytometry; Hematopoietic Stem Cells; Antigens, Differentiation; Polymerase Chain Reaction; Mice, Inbred C57BL; Mice; 03 medical and health sciences; Culture Techniques; Animals; Cell Lineage; Transcription Factors

Thymus cells of murine fetuses at day 12 of gestation are exclusively of the CD3-CD4-CD8-CD44+CD25- phenotype, which is known as a hallmark of the most immature subset of thymus cells. In the present study, we show that day 12 fetal thymus (FT) cells express Fc gamma RII/ III (FcR) at a broad range of levels on their surface. The FcR+ FT cells seem to represent T lineage cells, because a large majority of them express the T lineage specific transcription factors TCF-1 and GATA-3 as well as CD3 epsilon in the cytoplasm. Also shown is that the FcR- population contains progenitors capable of developing into not only T cells but also B and myeloid cells, whereas FcR+ progenitors are mostly committed to the T lineage. These findings indicate that thymic T lineage cells express FcR on their surface at the earliest stage of differentiation, and thus FcR is a useful marker in isolating the most immature population of murine FT cells.