NK cell colony formation from human fetal thymocytes.
We established a clonal cell culture system for human natural killer (NK) cells from fetal thymocytes. Thymocytes of 16 to 22 gestational weeks were cultured in methylcellulose in the presence of interleukin (IL)-7, IL-15, and steel factor (SF). After 14 days in incubation, large, diffuse colonies consisting of small cells were identified. Cells in the colonies were medium- to large-sized granular lymphocytes, expressing CD56 but not CD3, and revealed lytic activity against K562 cells. Colony-forming units (CFU)-NK were enriched in lineage negative (Lin- ) CD34++ subpopulations of fetal thymocytes, whereas a smaller number of CFU-NK also existed in Lin-CD34+ and Lin-CD34- subpopulations. Cytokine requirement for the NK cell colony formation was examined under serum-free conditions. As a single agent, only IL-15, but not IL-2, IL-7, or SF, supported NK cell colony formation. IL-15 had synergy with IL-7 and SF independently, and the maximal number of colonies were obtained when the three cytokines were present. IL-2 also supported NK cell colony formation in the presence of SF. When IL-2 was added to cultures containing IL-15 alone, IL-15 plus SF, or IL-15, SF, and IL-7, the numbers of NK cell colonies were reduced relative to those without IL-2. These results indicate that IL-2 may regulate IL-15-responsive NK cell progenitors. This clonal culture system will be a useful tool in the investigation of NK cell ontogeny.
Sato
T
T
Department of Pediatrics, Medical University of South Carolina, and Ralph H. Johnson Department of Veterans Affairs Medical Center, Charleston 29401-5799, USA.
Laver
J H
JH
Aiba
Y
Y
Ogawa
M
M
D015703:Antigens, CD / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002999:Clone Cells; D003114:Colony-Forming Units Assay; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004347:Drug Interactions; D005333:Fetus; D005434:Flow Cytometry; D006801:Humans; D007378:Interleukins / Q000494:pharmacology; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000166:cytology*; D019089:Stem Cell Factor / Q000494:pharmacology; D013950:Thymus Gland / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
D015703:Antigens, CD; D016895:Culture Media, Serum-Free; D007378:Interleukins; D019089:Stem Cell Factor