Analysis by in situ hybridization of cytokine mRNA expression in the murine developing thymus

Abstract

We have used in situ hybridization to investigate the expression of IL-1, IL-2, IL-4, IL-6 and IFN-gamma genes by thymic cells during fetal development in mice. Two waves of mRNAs were detected in thymic cells for IL-1 at days 16 and 19 of gestation, for IL-2 at days 14 and 18, and for IL-4 at days 14 and 16. Three peaks for IL-6 were observed at days 13, 17 and around birth. Finally, only one peak of cells positive for IFN-gamma was detected. Whereas cells positive for IL-1 were generally grouped and more often localized in the external area of the thymus, the other positive cells were isolated and evenly distributed in the thymus. Our results illustrated the presence of cytokine transcripts in the developing thymus following a developmentally controlled sequence and support the hypothesis that cytokines could play a role in T cell development.

Cytokine Gene Expression during Ontogeny in Murine Thymus on Activation of the Aryl Hydrocarbon Receptor by 2,3,7,8-Tetrachlorodibenzo-p-dioxin

“…The time course of intrathymic cytokine production seems to be essential for their role in controlling the thymocyte developmental program. Thus, several studies have been performed to establish the time course and expression strength of cytokines in the developing thymus (5,29,30). Moreover, studies in cytokine transgenic mice and in vitro studies in which cytokines were added to thymus organ cultures support a role for cytokines in thymocyte proliferation and/or differentiation and for the properties of the thymic microenvironment.…”

Thymus involution induced by mouse hepatitis virus A59 in BALB/c mice

“…On the other hand, several soluble molecules with growth factor or cytokine activity, including insulin-like growth factors, platelet-derived growth factor, interleukin-1, interleukin-3, interleukin-4, interleukin-6, interleukin-7, and interleukin-9, have been reported to protect cells against programmed cell death in some circumstances (1,22,37,40,48). Since thymic epithelial cells produce such molecules (12,18), infection of these cells, resulting in lysis or in impairment of their secretory activity, might lead to lymphocyte disappearance, which is suspected to be responsible for the increased susceptibility to apoptosis found in double-positive lymphocytes after inoculation with murine cytomegalovirus (31). In summary, our results show that the MHV-A59 receptor glycoprotein, MHVR, was expressed on thymus stromal cells, which are the principal targets for MHV-A59 infection in the thymus, but that MHVR expression was not detectable on thymic T lymphocytes which were relatively resistant to virus infection.…”

The IL‐2/IL‐2‐Receptor Complex in the Maturation of Rat T‐Cell Progenitors

“…In fact, the culture of T-cell progenitors with IL-2 promotes their differentiation to TcRcq3, TcRy6, and NK cells (Toribio et al, 1988;De la Hera et al, 1989;Brooks et al, 1993;He and Kabelitz, 1995), and in vivo or in vitro treatments that alter the IL-2/IL-2R complex profoundly modify the T-cell maturation (Jenkinson et al, 1987;Skinner et al, 1987;Tentori et al, 1988a;Plum et al, 1990;Waanders and Boyd, 1990;ZufiigaPflticke and Kruisbeek, 1990;Kroemer et al, 1991;Maslinski et al, 1992). Furthermore, two waves of IL-2 mRNA production, which correlate well with the differentiation of two waves of T-cell precursors (Jotereau et al, 1987;Penit and Vasseur, 1989), have been reported during fetal thymus development (Montgomery and Dallman 1991;Deman et al, 1994). Nevertheless, genedisruption experiments suggest that IL-2/IL-2R complex is not required for the generation of normal cell populations in the murine thymus (Schorle et al, 1991;Suzuki et al, 1995;Willerford et al, 1995).…”