Expansion of CD56+ NK T and gamma delta T cells from cord blood of human neonates.
A particular T cell population expressing NK cell markers, CD56 and CD57, exists in humans. Many CD56+ T and CD57+ T cells (i.e. NK T cells) exist in the liver and increase in number in the blood with ageing. They may be a human counterpart of extrathymic T cells, similar to NK1.1+ CD3int cells seen in mice. We investigate here the existence of such NK T cells in human cord blood and the in vitro expansion of these cells by the stimulation of human recombinant IL-2 (rIL-2). There were very small populations (< 1.0%) of CD56+ T cells, CD57+ T cells, and gamma delta T cells in cord blood. However, all of these populations increased in number after birth and with ageing. When lymphocytes in cord blood were cultured with rIL-2 (100 U/ml) for 14 days, CD56+ T cells expanded up to 25% of T cells. CD57+ T cells were never expanded by these in vitro cultures. The expansion of gamma delta T cells (mainly V gamma9- nonadult type) also occurred in the in vitro culture. A considerable proportion of CD56+ T cells was found to use V alpha24 (i.e. equivalent to invariant V alpha14 chain used by murine NK T cells) for TCR alpha beta. These results suggest that neonatal blood contains only a few NK T cells but CD56+ NK T cells and gamma delta T cells are able to expand in vitro.
Department of Immunology, Niigata University School of Medicine, Japan.
N
N
Musha
Y
Y
Yoshida
S
S
Sugahara
S
S
Yamagiwa
T
T
Koya
H
H
Watanabe
K
K
Hatakeyama
T
T
Abo
D000328:Adult; D000367:Age Factors; D019002:CD56 Antigen / Q000032:analysis*; D018959:CD57 Antigens / Q000032:analysis; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D005312:Fetal Blood / Q000166:cytology*; D006801:Humans; D007231:Infant, Newborn; D007376:Interleukin-2 / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology*; D008213:Lymphocyte Activation; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis*; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*
D019002:CD56 Antigen; D018959:CD57 Antigens; D007376:Interleukin-2; D016692:Receptors, Antigen, T-Cell, gamma-delta