Essential role of TNF receptor superfamily 25 (TNFRSF25) in the development of allergic lung inflammation

We identify the tumor necrosis factor receptor superfamily 25 (TNFRSF25)/TNFSF15 pair as critical trigger for allergic lung inflammation, which is a cardinal feature of asthma. TNFRSF25 (TNFR25) signals are required to exert T helper cell 2 (Th2) effector function in Th2-polarized CD4 cells and co-stimulate interleukin (IL)-13 production by glycosphingolipid-activated NKT cells. In vivo, antibody blockade of TNFSF15 (TL1A), which is the ligand for TNFR25, inhibits lung inflammation and production of Th2 cytokines such as IL-13, even when administered days after airway antigen exposure. Similarly, blockade of TNFR25 by a dominant-negative (DN) transgene, DN TNFR25, confers resistance to lung inflammation in mice. Allergic lung inflammation–resistant, NKT-deficient mice become susceptible upon adoptive transfer of wild-type NKT cells, but not after transfer of DN TNFR25 transgenic NKT cells. The TNFR25/TL1A pair appears to provide an early signal for Th2 cytokine production in the lung, and therefore may be a drug target in attempts to attenuate lung inflammation in asthmatics

Pleiotropic effects of Bcl-2 on transcription factors in T cells: potential role of NF-_KB p50–p50 for the anti-apoptotic function of Bcl-2

Bcl-2 functions to repress apoptosis by regulation of genes which encode proteins required for programmed cell death and by interference with peroxidative damage. We investigated the interrelationship between expression of bcl-2 and regulation of transcription factor DNA binding activities in the 2B4 T cell hybridoma and IL-2-dependent CTLL T cell line. Over-expression of bcl-2 in 2B4 resulted in enhanced basal levels of activator protein (AP)-1, octamer binding factor (Oct)-1, lymphoid enhancer binding factor (LEF)-1, RelA-p50 and NF-_KB p50–p50 DNA binding activities. After apoptotic signaling, down-regulation of AP-1, NF-AT and Oct-1 binding activities was observed in control 2B4 and CTLL, whereas suboptimal, but higher, levels of these transcription factors were found in bcl-2-transfected cells, potentially promoting cell survival. Furthermore, after apoptotic signaling, expression of bcl-2 led to differential changes of NF-_KB levels, resulting in a decrease in RelA-p50 and an increase In NF-_KB p50–p50, altering the ratio of these DNA binding activities such that now p50–p50 markedly predominated in both 2B4-Bcl-2 and CTLL-Bcl-2. Apoptotic signaling in the presence or absence of Bcl-2 resulted in induction of the RelB-p50 heterodimer in 2B4. The changes in NF-_KB/ROI levels raise the possibility that this family of transcription factors may play an important role in the regulation of apoptosis

Regulation of Fas-Dependent Activation-Induced T cell Apoptosis by cAMP Signaling: A Potential Role for Transcription Factor NF-κB

TCR-mediated activation of T cell hybridomas induces programmed cell death by a Fas-dependent pathway. We now show that costimulation of 2B4 cells, in the absence or presence of transgenic Bcl-2, with anti-CD3epsilon and forskolin, an activator of cAMP signaling, resulted in antagonism of Fas-dependent activation-induced cell death that was always accompanied by selective down-regulation of the nuclear levels of NF-κB p65-p50 (RelA-p50) transcription factor. Forskolin not only inhibited activation-induced cell death and NF-κB activation, but also suppressed expression of Fas and Fas ligand (Fas-L). Furthermore, NF-κB p65 antisense oligonucleotide down-regulated nuclear levels of NF-κB, inhibited cell surface expression of Fas-L and apoptosis of 2B4. Collectively, these finding demonstrate a potential role of NF-κB in the regulation of activation-induced apoptosis in T lymphocytes

Assessment of Perforin Expression in Peripheral Blood Lymphocytes in Psoriatic Patients During Exacerbation of Disease

There are very few data concerning the role played by cellmediated cytotoxicity, particularly at the molecular level, in the course of psoriasis. Both cytotoxic T lymphocytes (CTL) and natural killer cells contain in their granules the cytolytic protein perforin, a mediator in cell-mediated cytotoxicity reactions. The aim of this study was to analyze perforin expression in various sets and subsets of perforin-positive peripheral blood lymphocytes in 17 patients with chronic psoriasis vulgaris in the exacerbation phase. The results were compared with those of an age- and sex-matched healthy control group (n= 21). Perforin (intracellular antigen) and cell surface antigens were detected using the simultaneous double-staining method. We found a signi®cant increase in perforin (P) expression in the patient group for CTL (CD3+ P+ cells), which are located mostly in the CD8+ population of T lymphocytes (CD8+ P+ )

Perforin Is Required for Innate and Adaptive Immunity Induced by Heat Shock Protein Gp96

Tumor-secreted gp96-Ig is highly immunogenic and triggers CD8 T cell-mediated tumor rejection. In vivo secreted gp96-Ig and gp96-myc cause NK activation and clonal expansion of specific CD8+ CTL in wild-type and in Fas-ligand-deficient (gld) mice but not in perforin- (PKO) or IFN-γ-deficient (GKO) mice. Transfer of perforin-competent NK cells restores the ability of PKO mice to clonally expand CD8 CTL in response to gp96-Ig. The data demonstrate an essential role for perforin-mediated functions in the activation of innate and adaptive immunity by heat shock protein gp96-peptide complexes. Crosspresentation of antigens by heat shock proteins seems to require a perforin-dependent positive feedback loop between NK and DC for both sustained NK activation and clonal CTL expansion. The studies also explain how depressed NK activity in patients with tumors or after viral infections could diminish CTL responses

Pulmonary Nontuberculous Mycobacterial Infection. A Multisystem, Multigenic Disease

Rationale: The clinical features of patients infected with pulmonary nontuberculous mycobacteria (PNTM) are well described, but the genetic components of infection susceptibility are not