Release of IL-1beta via IL-1beta-converting enzyme in a skin dendritic cell line exposed to 2,4-dinitrofluorobenzene.

We used a mouse fetal skin dendritic cell line (FSDC) to study the effect of the strong allergen 2,4-dinitrofluorobenzene (DNFB) on interleukin (IL)-1beta release and IL-1beta receptor immunoreactivity. Stimulation with DNFB (30 minutes) increased IL-1 release without changing the mRNA levels of the protein. Furthermore, DNFB increased transiently the interleukin-1beta-converting enzyme (ICE) activity, as measured with its fluorogenic substrate Z-Tyr-Val-Ala-Asp-AFC.

Homeostasis of naive and memory CD4+ T cells: IL-2 and IL-7 differentially regulate the balance between proliferation and Fas-mediated apoptosis.

Cytokines play a crucial role in the maintenance of polyclonal naive and memory T cell populations. It has previously been shown that ex vivo, the IL-7 cytokine induces the proliferation of naive recent thymic emigrants (RTE) isolated from umbilical cord blood but not mature adult-derived naive and memory human CD4(+) T cells. We find that the combination of IL-2 and IL-7 strongly promotes the proliferation of RTE, whereas adult CD4(+) T cells remain relatively unresponsive.

Ex vivo isolation protocols differentially affect the phenotype of human CD4+ T cells.

Leukemic T cell lines have facilitated signal transduction studies but their physiological relevance is restricted. The use of primary T lymphocytes overcomes this limitation but it has long been speculated that methodological aspects of blood collection and the isolation procedure modify the phenotype of the cell. Here we demonstrate that several characteristics of human peripheral T cells are affected by the selection conditions.

IL-7 differentially regulates cell cycle progression and HIV-1-based vector infection in neonatal and adult CD4+ T cells.

Differences in the immunological reactivity of umbilical cord (UC) and adult peripheral blood (APB) T cells are poorly understood. Here, we show that IL-7, a cytokine involved in lymphoid homeostasis, has distinct regulatory effects on APB and UC lymphocytes. Neither naive nor memory APB CD4(+) cells proliferated in response to IL-7, whereas naive UC CD4(+) lymphocytes underwent multiple divisions.