The effect of transforming growth factor-beta on the expression of CD8 in the CTLL-2 cell line / 천식및알레르기

BACKGROUND: Transforming growth factor-beta(TGF-beta) has multiple regulatory effects on cells of the immune system, and it has been suggested that differentiation of lymphoid cells is influenced by low concentra tions of this cytokine. OBJECTIVES: The aim or this study was to investigate the role of TGF-beta in regulation of T cell growth and differentiation, and to compare this effect with that of other cell signals known to be important in T cell ontogeny. METHODS: We used the CTLL-2 cell line in the presence of IL-2. Surface phenotype expression was analysed to see whether these cells could be switched to the other subtype of cells. RESULT: Treatment of CTLL-2 cells with TGF-beta resulted in dose dependent growth inhibition and morphological changes. Curing routine passage, less than 5% of cells were CD8alpha positive, whereas 38% of cells expressed CD8alpha when treated with IL-2 plus TGF-beta. However, TPA plus calcium ionophore, IFN-gamma, or TNF-alpha caused no significant changes in the proportion of CD8 cells. CONCLUSION: Our results show that this experiment can be a useful model for investigating CD8 precursor potentials in populations of CD4-CD8-(double negative) cells, and such a model may offer a way to study the molecular regulation of CD8 gene expression.

A highly sensitive, modified assay for Interleukin-1 / 中国免疫学杂志

In this paper, we describe a highly sensitive, modified assay which takes advantage of the capacity of a mouse thymoma cell line EL4 subclone to produce high concentration of IL-2 upon stimulation by interleukin I (IL-1).The assay was generally performed in 2 stages which included IL-1-dependent IL-2 production and IL-2 biological activity assay, and took about 40 hours to complete. The sensitivity of this assay was got to be 10~(-2) ～10~(-4)U/ml (2.5～25?10~(-4)pg/ml, about 10~2～10~3 times more sensitive than that of the mouse thymocyte co-stimulated assay) by selecting the optimal serum concentration, EL 4 cell density, IL-1-induced time and EL4 supernatant dilution. The rapid one step assay was performed by co-culturing the EL4 cells with CTLL-2 cells. This rapid assay could be completed within 30 hours with sensitivity of 10~(-1)U/ml. The assay was not affected by high concentrations of rHuTNF- ?, rHuTNF- ? or rHuIL-6,and was only slightly affected by high concentrations of rHuIL-2, ConA, PHA,LPS and SEB, and much affected by A23187.