Extrathymic differentiation of T lymphocytes and natural killer cells from human embryonic liver precursors.
Liver cells were isolated on Ficoll/Hypaque gradients from embryos or fetuses at 6-10 weeks of gestation; 2-20% of the cells expressed CD45 or HLA class I surface antigens and 2-6% expressed CD7. Other T- or natural-killer (NK)-cell-lineage-specific markers were undetectable. Liver-cell suspensions cultured in the presence of phytohemagglutinin and recombinant interleukin 2 gave rise to large proportions of CD3+ lymphocytes expressing either alpha/beta or gamma/delta T-cell receptors. This occurred not only in bulk cultures but also when cells were cloned under limiting dilution conditions. Importantly, these figures were obtained also in embryos at 6-8 weeks of gestation, which is before colonization of the thymic rudiment by T-cell precursors. When the same liver-cell suspensions were cultured in the presence of irradiated H9 cells and recombinant interleukin 2 (either in bulk cultures or under cloning conditions), large proportions of cells (or clones) expressed surface CD16 and CD56 antigens and displayed a strong cytolytic activity against both NK-sensitive (K562) and NK-resistant (M14) target cells. In addition, liver-derived T or NK cells expressed functional receptor molecules since they could be activated via either CD3/T-cell receptor or CD16 surface antigens, respectively. Further fractionation of liver cells on the basis of CD45 antigen expression indicated that only CD45+ cells could give rise to T or NK cells in culture. Thus, CD45 can be used as a marker for identification of an early liver-cell population containing T- and NK-cell precursors. That T or NK cells were derived from male embryos and not from the mother was shown by PCR amplification of X and Y chromosomal sequences. Our present data may offer an in vitro model for extrathymic embryonic T-cell maturation that can be used to examine fundamental aspects of human T-cell development and function.
Poggi
A
A
Instituto Nazionale per la Ricerca sul Cancro, Genoa, Italy.
Sargiacomo
M
M
Biassoni
R
R
Pella
N
N
Sivori
S
S
Revello
V
V
Costa
P
P
Valtieri
M
M
Russo
G
G
Mingari
M C
MC
D017252:CD3 Complex / Q000032:analysis; D002454:Cell Differentiation; D002455:Cell Division; D002999:Clone Cells; D006801:Humans; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000166:cytology*; D017493:Leukocyte Common Antigens / Q000032:analysis; D008099:Liver / Q000196:embryology*; D008297:Male; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism; D017452:Receptors, IgG / Q000032:analysis; D016176:T-Lymphocyte Subsets / Q000166:cytology*; D013950:Thymus Gland / Q000196:embryology
D017252:CD3 Complex; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D017452:Receptors, IgG; D017493:Leukocyte Common Antigens