A population of early fetal thymocytes expressing Fc gamma RII/III contains precursors of T lymphocytes and natural killer cells.
We have identified a dominant fetal thymocyte population at day 14.5 of gestation in the mouse that lacks CD4 and CD8 but expresses Fc gamma RII/III several days prior to acquisition of the T cell receptor (TCR) in vivo. If maintained in a thymic microenvironment, this population of CD4-CD8-TCR-Fc gamma RII/III+ thymocytes differentiates first into CD4+CD8+TCRlowFc gamma RII/III- thymocytes and subsequently CD4+CD8-TCRhighFc gamma RII/III- and CD4-CD8+TCRhighFc gamma RII/III- mature Ti alpha-beta lineage T cells. However, if removed from the thymus, the CD4-CD8-TCR-Fc gamma RII/III+ thymocyte population selectively generates functional natural killer (NK) cells in vivo as well as in vitro. These findings show that a cellular pool of Fc gamma RII/III+ precursors gives rise to T and NK lineages in a microenvironment-dependent manner. Moreover, they suggest a hitherto unrecognized role for Fc receptors on primitive T cells.
Rodewald
H R
HR
Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
Moingeon
P
P
Lucich
J L
JL
Dosiou
C
C
Lopez
P
P
Reinherz
E L
EL
D000818:Animals; D015703:Antigens, CD / Q000276:immunology*; D000943:Antigens, Differentiation / Q000276:immunology*; D001483:Base Sequence; D002454:Cell Differentiation / Q000276:immunology; D003601:Cytotoxicity Tests, Immunologic; D005333:Fetus / Q000276:immunology; D005434:Flow Cytometry; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011961:Receptors, Fc / Q000276:immunology*; D017452:Receptors, IgG; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000196:embryology / Q000276:immunology
D015703:Antigens, CD; D000943:Antigens, Differentiation; D011961:Receptors, Fc; D017452:Receptors, IgG