Effector Function of Diabetogenic CD4 Th1 T Cell Clones: A Central Role for TNF-α

Abstract

Effector function of T cells in autoimmune diabetes has been widely studied with mixed populations of lymphoid T cells stimulated ex vivo, but this approach does not permit evaluation of the contribution by a single T cell clone in the inflammatory site during pathogenesis. We have investigated cytokine production both in vitro and in vivo in a panel of diabetogenic CD4 Th1 T cell clones derived from the NOD mouse. SuperArray analysis showed a common pattern of mRNA expression for inflammatory cytokines and receptors in vitro after TCR stimulation. Ex vivo intracellular cytokine staining demonstrated that two important inflammatory cytokines, IFN-γ and TNF-α, were being made by these T cells recovered from the pancreas 6 days following adoptive transfer. TNF-α produced in the pancreas by pathogenic T cell clones and recruited macrophages was not the membrane-bound form. Secreted TNF-α can lead to production of multiple inflammatory chemokines, as were observed in the pathogenic clones by intracellular cytokine staining. Our results not only define the nature of an inflammatory cytokine response critical to development of diabetes, but also suggest its role in the regulation of other events during pathogenesis induced by CD4 T cells. Similar analyses in other models demonstrated that disease induced by CD4 T cell clones closely resembles spontaneous autoimmune diabetes in which both CD4 and CD8 T cells are required. Thus, cloned T cells in effect amplify effector function of T cells which otherwise may be difficult to detect without ex vivo stimulation.

NF-κB prevents β cell death and autoimmune diabetes in NOD mice

“…Neutralization of TNF-␣ blocked disease development after transfer of diabetogenic CD4 ϩ T cells into RIP-mI B␣/NOD mice. Consistent with our results, a recent paper (45) showed that diabetogenic CD4 ϩ T cells produce TNF-␣ and IFN-␥, which are highly representative of cytokines in natural T1D. Furthermore, targeted disruption of IL-1 receptor (46), caspase-1, which converts pro-IL-1␤ to active IL-1␤ (47) or iNOS (J. Fenyk-Melody and J. S. Mudgett, personal communication) have little protective effects on the development of T1D in NOD mice.…”

Fluorine‐19 MRI for visualization and quantification of cell migration in a diabetes model

“…It shares many of the genetic and immunological features of the human disease, including the presence of diabetogenic T cells and spontaneous development of diabetes. The T1D model using adoptive transfer of NOD BDC2.5 T cells is well established (22,36). CD4 ϩ T cells play a key role in diabetogenesis, and their ability to cause diabetes in adult NOD SCID mice is accelerated when the mice are pretreated with cyclophosphamide (20), and this allowed us to observe infiltrating T cells at an early and predictable time after injection.…”

“…CD4 ϩ T cells play a key role in diabetogenesis, and their ability to cause diabetes in adult NOD SCID mice is accelerated when the mice are pretreated with cyclophosphamide (20), and this allowed us to observe infiltrating T cells at an early and predictable time after injection. Activated BDC2.5 T cells of both Th1 and Th2 type can rapidly induce diabetes in NOD SCID (22,37). This model, although artificial, created a useful platform for optimizing the quantitative aspects of these techniques.…”

“…For all in vivo experiments we used an established adoptive transfer method that has been shown to result in reproducible diabetes induction (22,23). The BDC2.5 T cells (Ϸ4 ϫ 10 6 ) were purified, activated in vitro, PFPE-labeled, and injected i.p.…”

Pathogenic Mechanisms in Type 1 Diabetes: The Islet is Both Target and Driver of Disease

“…Overall the significant effect of perforin deficiency points overwhelmingly to its dominant role in CTL-mediated beta-cell destruction in vivo (Figure 2, Table 1). Perforin deficiency does not reduce diabetes mediated by CD4 + T cells, demonstrating this is unlikely to be a dominant effector mechanism utilized by CD4 + T cells [94,95]. The main function of perforin is to facilitate the activation and delivery of granzymes into the target cell.…”