The effect of TGF-beta on the induction CD8 and NK1.1 expression in CTLL-2 cell line.
BACKGROUND
The presence of CD8+ T-cells expressing NK cell associated markers (TNK cells) has been observed in several experimental models, which suggests that NK cells may belong to the T-cell lineage. We used the CTLL-2 cell line, which is NK1.1+ CD3- TCR+ CD4- CD8- cells in the presence of IL-2, to investigate whether these cells can be switched to CD8+ or CD4+ cells, like TNK cells, by the TGF-beta.


METHODS
CTLL-2 cells were cultured with TGF-beta or other cytokines and activators in the presence of IL-2. In order to see the surface and intracytoplasmic antigen expression in a single-cell level, simultaneous surface CD4, CD8, TCR with NK1.1, and intracytoplasmic NK1.1 staining was performed and three-color flow cytometric analysis was performed.


RESULTS
During routine passage, less than 5% of cells were CD8a+, although 20-40% of cells expressed CD8a when treated with IL-2 + TGF-beta, whereas TPA + Calcium ionophore, IFN-gamma, and TNF-alpha cause no significant changes in the proportion of CD8+ cells. Twenty percent of CTLL-2 cells expressed NK1.1 with IL-2 treatment, and this expression was also increased up to 65%-70% with IL-2 + TNF-beta. Furthermore, most of the CD8 positive cells showed intracytoplasmic NK1.1.


CONCLUSIONS
Our results indicated that these would be useful models to investigate CD8 precursor potentials in populations of CD4-CD8- (double negative) cells and the relationship of NK1.1. These results also support a role for TGF-beta in T-cell differentiation and the hypothesis that T-cells and NK cells may have the same ontogeny.
Cho
Y J
YJ
Dept. of Medicine, Ewha Women's University, College of Medicine, Ewha Women's Research Center, Seoul, Korea. yjcho@ewha.ac.kr
Lee
J S
JS
D000818:Animals; D017252:CD3 Complex / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis*; D002478:Cells, Cultured; D005434:Flow Cytometry; D007376:Interleukin-2 / Q000502:physiology; D007694:Killer Cells, Natural / Q000276:immunology*; D051379:Mice; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000502:physiology*
D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D016212:Transforming Growth Factor beta