Immunoregulation and TGF-beta 1. Suppression of a nephritogenic murine T cell clone

Transforming growth factor beta (TGF-beta) has been clearly linked in several model systems to the development of pathologic extracellular matrix deposition in the glomerulus and interstitium. TGF-beta additionally exerts multiple immunomodulatory effects on T and B lymphocytes, including growth inhibition. Such pleiotropic effects make it difficult to predict how TGF-beta might directionally affect the expression of T cell mediated kidney disease. We have examined the effects of TGF-beta 1 on the activity of effector T cells in a model of autoimmune interstitial nephritis. M52.26 is an antigen-specific, nephritogenic, cytotoxic T cell clone. TGF-beta 1 mediates a concentration-dependent inhibition of M52.26-directed cytotoxicity of tubular epithelial cells in culture, and also of M52.26-mediated transfer of interstitial nephritis to syngeneic recipients. The loss of these functional activities is associated with distinct changes in cytokine gene expression in M52.26. These cytokine alterations consist of a loss of IFN-gamma and perforin expression, and an up-regulation of TGF-beta expression, which is likely relevant to the observed effector T cell inactivation.

Inhibition of murine nephritogenic effector T cells by a clone-specific suppressor factor

We have used a murine model of organ-specific autoimmunity to characterize therapeutic modalities capable of down-regulating the cellular limb of the autoimmune response. Murine interstitial nephritis is an autoimmune disease mediated by tubular antigen-specific CD8+ nephritogenic effector T cells which are delayed-type hypersensitivity (DTH) reactive and cytotoxic to renal epithelial cells. Previous studies have demonstrated that disease can be suppressed with experimentally induced populations of T cells (Ts1 and Ts2 cells) obtained after injection of tubular antigen-coupled splenocytes into syngeneic mice. As the target of Ts2 is the CD8+ effector T cell, we have evaluated its effects on nephritogenic effector T cell clones isolated from diseased animals. Our studies demonstrate that soluble proteins expressed by Ts2 cells (TsF2) specifically abrogate the DTH, cytotoxic, and nephritogenic potential of M52 cells, although T cell receptor and IL-2 receptor expression are unchanged in these unresponsive M52 clones. TsF2-induced inhibition is dependent on new mRNA and protein synthesis. In a cytotoxic clone, M52.26, exposure to TsF2 induces expression of TGF-beta 1 which is, in turn, required for inhibition of cytotoxicity and nephritogenicity. Our studies are consistent with TGF-beta 1 behaving, at least in some T cells, as a nonspecific final effector of clone-specific suppression.

Molecular analysis of the helper T cell response in murine interstitial nephritis. T cells recognizing an immunodominant epitope use multiple T cell receptor V beta genes with similarities across CDR3

Anti-tubular basement membrane disease (alpha TBM disease) produces T cell-mediated interstitial nephritis in SJL mice after immunization with renal tubular antigen. Initial mononuclear infiltrates appear in vivo after several weeks, with the subsequent progression to renal fibrosis and end stage renal disease over many months. We have analyzed the fine specificity of the autoreactive helper T cell repertoire in alpha TBM disease through the isolation and characterization of a panel of CD4+ Th1 clones harvested after 1-2 wk from animals immunized to produce disease. All clones capable of mediating alpha TBM disease are directed towards a 14-residue immunodominant epitope (STMSAEVPEAASEA) contained within the target antigen, 3M-1. Evaluation of the T cell receptor (TCR) V beta repertoire used by these autoreactive T cells reveals the use of several V beta genes, but with some preference for V beta 14. Sequencing across the putative CDR3 region of the TCR beta chains suggests that common amino acids at the V beta(N)D beta junction and the D beta(N)J beta junction may contribute to the specific ability of these cells to recognize the immunodominant epitope.

Nitric oxide (endothelium-derived relaxing factor) attenuates revascularization-induced lung injury

Aortic occlusion and revascularization (I-R) may lead to lung injury dependent on activated neutrophil adherence. Nitric oxide (NO) inhibits neutrophil adherence to endothelial cells. We studied the effect of increasing or decreasing NO levels with sodium nitroprusside (SNP) or N-nitro-L-arginine methyl ester (L-NAME) in an I-R lung injury model of 30 min ischemia followed by 120 min reperfusion. Sprague-Dawley rats (10/group) were randomized to controls, I-R, I-R treated with L-NAME (10 mg/ml/hr), and I-R treated with SNP (0.2 mg/ml/hr). Myeloperoxidase activity (MPO) was used as a measure of pulmonary neutrophil influx. Pulmonary endothelial permeability was measured by wet:dry weight ratio and bronchoalveolar lavage protein (BAL prot) and neutrophil counts (BAL PMN). Aortic occlusion and revascularization led to significant increases in pulmonary neutrophil influx (6.1 +/- 0.1 MPO u/g vs 3.05 +/- 0.4 MPO u/g in the control group, P < 0.001) and microvascular leakage; BAL prot (347 +/- 32 mg/ml in controls vs 454 +/- 16 mg/ml in the I-R group, P < 0.05); and BAL PMN (0.7 +/- 0.05 in controls vs 1.8 +/- 0.07 PMN/ml in the I-R group, P < 0.001). These changes were exacerbated further by administration of L-NAME (MPO = 8.9 +/- 0.7; BAL prot = 581 +/- 40 mg/ml; BAL PMN = 2.7 +/- 0.16 PMN/ml). Sodium nitroprusside therapy attenuated the I-R-induced lung injury (3.5 +/- 0.4 MPO u/g, P < 0.05 vs I-R; BAL prot = 330 +/- 61 mg/ml; BAL PMN = 0.9 +/- 0.1 PMN/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in macrophage signal transduction pathways mediate post-traumatic changes in macrophage function

After injury, macrophage effector function diminishes while suppressor function increases. Protein kinase C (PKC), which initiates superoxide synthesis and phagocytosis, and phospholipase A2 (PLA2), which initiates eicosanoid metabolism, are key enzymes in cell signal transduction, which may mediate this change in cell function. The aim of this study was to investigate the effect of trauma on macrophage signal transduction. Swiss-Webster (CFW) mice (n = 210) were randomized to control or hindlimb amputation groups. Animals were sacrificed 24 hr after injury. Peritoneal macrophage function was assessed by measurement of superoxide anion (O2-), Fc, mannose-fucose-mediated phagocytosis, and PGE2 release. Membrane and cytosolic PKC activity were measured by radioimmunoassay in unstimulated and phorbol ester-stimulated cells. Membrane fatty acids and PLA2 activity were measured by thin-layer chromatography. Hindlimb amputation resulted in significantly decreased superoxide anion synthesis (0.7 +/- 0.2 nm vs 1.7 +/- 0.3 nmol/l/10(6) cells in controls, P < 0.01) and phagocytosis and a significant increase in prostaglandin E2 synthesis. This was associated with a shift in cell membrane metabolism with increased PLA2 activity, arachidonic acid turnover, and a significant reduction in PKC membrane translocation in response to phorbol ester. Together these data demonstrate an alteration in signal transduction pathways, which may account for the observed change in macrophage function after injury.

Inherited interstitial nephritis in kdkd mice

kdkd mice, a mutant subline of CBA/Ca mice, develop a progressive, T cell-mediated, autoimmune interstitial nephritis which leads to renal failure and death of all mice at 20-28 weeks of age. This disease is inherited in an autosomal recessive manner, with complete penetrance, and has been linked to grizzled and waltzer on mouse chromosome 10. Immunologic evaluation of this lesion has demonstrated that histologic disease is initiated by a population of CD8+, H-2Kk-restricted T cells, which recognize an antigen in collagenase-solubilized syngeneic renal tubules. These nephritogenic effector cells can also be demonstrated in non-disease prone CBA/Ca mice. Susceptibility to autoimmune nephritis correlates with distinct expression of regulatory, rather than effector, T cells. Interstitial nephritis in kdkd mice can be inhibited by protein-calorie restriction, infusions of CBA/Ca CD8+ T cells, or monoclonal antibodies of ICAM-1. This murine model most closely resembles medullary cystic disease in humans, which has not historically been considered an autoimmune disease. Mapping of the genes for both medullary cystic disease and the defect in kdkd mice should augment our understanding of mechanisms of organ-specific autoimmunity.

T cell function in chronic renal failure and dialysis

This article briefly summarizes the literature regarding possible defects in cell-mediated immunity in the setting of chronic renal failure. It is difficult to precisely determine the proximate cause or level of such defects from most studies. Confounding variables include reports on mixed patient populations (predialytic chronic renal failure, hemodialysis patients, and peritoneal dialysis patients) and studies before and after the introduction of erythropoietin for end-stage renal disease patients. While it seems clear that lymphopenia, suboptimal responses to mitogens, abnormal cytokine gene expression, and abnormal IL-2R expression are seen in a number of dialysis patients, the role of uremia versus dialysis in producing these abnormalities is unclear. In addition, it is difficult to determine whether T cell abnormalities are primary or secondary to impaired function of other interacting immune cells, such as macrophages. Clinical implications of defects in cell-mediated immunity are additionally discussed.

Role of bactericidal permeability-increasing protein in the treatment of gram-negative pneumonia

BACKGROUND

Gram-negative infections are a major cause of morbidity and death. Bactericidal permeability-increasing protein (BPI) is an endotoxin-neutralizing protein that also exhibits potent bactericidal activity. This study compared the efficacy of a 23 kd recombinant N-terminal fragment of BPI (rBPI23) with that of antiendotoxin antibody E5 in a model of gram-negative sepsis.

METHODS

Sixty Swiss-Webster mice (Carworth farm) received an intratracheal inoculation of Escherichia coli (7 x 10(6) colony-forming units) and were randomized to three groups (20 per group). Starting immediately after inoculation, the groups received either rBPI23 (4 mg/kg intravenously every 2 hours for four doses), E5 (11 mg/kg intravenously every 24 hours for two doses), or an isotype control antibody B55 (11 mg/kg intravenously every 24 hours for two doses) and were followed up for survival. In a second survival study, 40 mice received the same intratracheal inoculation of E. coli and were randomized to two groups. Starting 2 hours after inoculation, the groups received either rBPI23 (4 mg/kg intravenously every 2 hours for four doses) or E5 (8 mg/kg intravenously every 12 hours for four doses) and were followed up for survival. In a third study, mice received an intratracheal inoculation of 3 x 10(6) colony-forming units E. coli, a sublethal dose, and were killed to determine pulmonary and blood clearance of bacteria.

RESULTS

rBPI23 conferred significantly greater protection from death than either E5 or B55 when started immediately (95% survival vs 20% and 10%, respectively; p < 0.001) or 2 hours after inoculation (65% survival vs 25% for E5; p < 0.05). Both pulmonary and vascular clearance of bacteria was enhanced significantly by treatment with rBPI23.

CONCLUSIONS

rBPI23 may be a novel therapeutic agent in the management of gram-negative sepsis.

Macrophage-dependent candidacidal mechanisms in the murine system. Comparison of murine Kupffer cell and peritoneal macrophage candidacidal mechanisms

Candida albicans infection is common in immunocompromised patients. The role of fixed tissue macrophages (M phi), including Kupffer cells (KC) and peritoneal macrophages (PM phi), in host defense against C. albicans is unclear. This study examined murine M phi candidacidal mechanisms and evaluated the in vitro role of the macrophage-activating factor IFN-gamma in augmenting these mechanisms. The effect of in vivo administration of IFN-gamma on survival after lethal C. albicans challenge in the murine system was also assessed. Percent PM phi and KC ingestion of C. albicans were similar. Prior opsonization of Candida increased the percentage of M phi ingestion of this pathogen. PM phi and KC phagocytic function was similar for both nonopsonized and opsonized C. albicans, but KC demonstrated markedly decreased ability to kill this pathogen (O2-, Candida killing). IFN-gamma enhanced KC and PM phi candidacidal activity. PM phi and KC Ag presentation was increased in early Candida infection, but diminished in established infection, when the majority of animals died. C. albicans failed to elicit significant amounts of either IL-1 or TNF compared with LPS stimulation of PM phi and KC in vitro. IFN-gamma treatment in vivo was associated with significantly improved survival (p &lt; 0.01).

Macrophage-dependent candidacidal mechanisms in the murine system. Comparison of murine Kupffer cell and peritoneal macrophage candidacidal mechanisms

Candida albicans infection is common in immunocompromised patients. The role of fixed tissue macrophages (M phi), including Kupffer cells (KC) and peritoneal macrophages (PM phi), in host defense against C. albicans is unclear. This study examined murine M phi candidacidal mechanisms and evaluated the in vitro role of the macrophage-activating factor IFN-gamma in augmenting these mechanisms. The effect of in vivo administration of IFN-gamma on survival after lethal C. albicans challenge in the murine system was also assessed. Percent PM phi and KC ingestion of C. albicans were similar. Prior opsonization of Candida increased the percentage of M phi ingestion of this pathogen. PM phi and KC phagocytic function was similar for both nonopsonized and opsonized C. albicans, but KC demonstrated markedly decreased ability to kill this pathogen (O2-, Candida killing). IFN-gamma enhanced KC and PM phi candidacidal activity. PM phi and KC Ag presentation was increased in early Candida infection, but diminished in established infection, when the majority of animals died. C. albicans failed to elicit significant amounts of either IL-1 or TNF compared with LPS stimulation of PM phi and KC in vitro. IFN-gamma treatment in vivo was associated with significantly improved survival (p < 0.01).

Perioperative care of the oncology patient

Cancer patients are often at high risk for perioperative complications because of preexisting conditions, the magnitude of surgery, and the use of aggressive multimodality treatment. It is essential to identify risk factors preoperatively, correct any deficits, and monitor organ dysfunction. During the perioperative period prophylaxis and surveillance for cardiopulmonary, hematologic, and septic complications should minimize morbidity and mortality. Finally, nutritional support should be given to malnourished patients undergoing extensive operative procedures.

Colorectal cancer. Principles of postoperative follow-up

Monitoring patients after primary large bowel surgery for malignancy is predicated on the concept that early detection of recurrence may provide salvage treatment for cure. Knowledge of the pathologic site and stage provides important information as to the probability of recurrence and the patterns of failure that are likely to occur. Available methods to detect recurrence include clinical, roentgenographic, and serum tests that are done more frequently during the first 2 years after surgery. Monitoring plasma carcinoembryonic antigen levels can lead to identification of asymptomatic recurrences, but there is controversy about the curability of recurrences outside the liver. Newer techniques (such as computed tomographic portography, intraoperative ultrasonography, and radioimmunoguided surgery) provide greater diagnostic accuracy and lead to more appropriate procedures during "second-look" operations. For example, hepatic resection in properly selected patients offers up to a 30% chance of cure and should be pursued aggressively. A search for metachronous cancers by endoscopy also should be done. Knowledge of the potential and patterns of failure can provide a useful guide during the postoperative follow-up care of the patient with large bowel cancer.

Effects of laparotomy on systemic macrophage function

Surgical trauma induces immunosuppression that may adversely influence survival. This study examined the effect of laparotomy on two different macrophage populations, peritoneal macrophages (PM phi) and Kupffer cells. Female, 6- to 8-week old, CFW/C3H-HeN mice (n = 160) were randomly allocated to one of three study groups: control, ether anesthetic only, or ether anesthetic and laparotomy. On postoperative days 1 and 3, PM phis and Kupffer cells were harvested and assayed for superoxide anion production (O2-), percent macrophage phagocytosis of Candida albicans (CAP), percent C. albicans killed by macrophages (CAK), percent major histocompatibility complex (MHC)-class II antigen expression, and antigen presentation. Macrophages isolated on postoperative day 1 were also cocultured with 100 units/10(6) cells/ml interferon-gamma (IFN-gamma). Laparotomy significantly impaired microbicidal activity (O2-, percent CAP, and percent CAK) and antigen presentation on postoperative day 1. On postoperative day 3, O2- and antigen presentation were increased significantly (p less than 0.05) over control values, indicating a rebound phenomenon. Kupffer cell microbicidal function was unchanged on postoperative days 1 and 3. The initial immune impairment (PM phis: O2-, CAP, and CAK) was abrogated by IFN-gamma treatment. In immunosuppressed hosts after injury, administration of macrophage-activating factors such as IFN-gamma could be of therapeutic benefit.

Anti-neoplastic effects of interleukin-4

Interleukin-4 (IL-4) is a cytokine, with potential anti-neoplastic effects. This study examined the effects of IL-4 on host anti-tumor responses in a murine model. C57/B16 mice (n = 40) were randomized to receive Lewis lung carcinoma (10(6) cells: right flank; sc) or saline, and sacrificed 10 days postinoculation for assessment of peritoneal macrophage (PMO) anti-tumor mechanisms [superoxide anion generation (O2-), tumor necrosis factor (TNF), and TNF-independent (P815) cytotoxicity], splenocyte mixed lymphocyte response (MLR) (Balb/c stimulator), and cytotoxic lymphocyte generation (CTL against P815). Cells were cultured +/- IL-4 (100 U/ml). In a second study, 20 mice received Lewis lung implants (sc) and were randomized on Day 21 to receive daily IL-4 (1000 U/mouse; ip) or saline. Tumor volumes and median survival were assessed. Tumor necrosis factor-independent cytotoxicity (O2-, MLR and CTL) was impaired in the tumor-bearing (TB) study group. Interleukin-4 administered to cultured cells from TB mice enhanced O2-, as well as MLR and CTL (P less than 0.01), and decreased TNF release but did not alter PM phi TNF-independent anti-tumor responses (P815). In vivo administration of IL-4 significantly decreased tumor growth (P less than 0.05) after 10 days of treatment and significantly prolonged median host survival (P less than 0.05). These findings indicate the therapeutic potential of IL-4 in the TB host which may function through downregulation of TNF production while potentiating certain T cell-dependent and independent anti-tumor immune mechanisms.

Tubular antigen-binding proteins repress transcription of type IV collagen in the autoimmune target epithelium of experimental interstitial nephritis

We have been studying immune interactions with somatic cells using a tubular antigen-binding protein (ThF) secreted by helper T lymphocytes harvested from mice that have an autoimmune form of interstitial nephritis called anti-tubular basement membrane disease. This ThF, although characterized originally because of its ability to induce effector T cells, additionally recognizes the nephritogenic 3M-1 antigen expressed by its target renal tubular epithelium. We believe these proteins, in general, may modulate directly some homeostatic functions in organ-derived cells, and now report that our ThF represses specifically the cellular transcription and secretion of basement membrane type IV collagen in tubular epithelium. These in vitro findings of reduced levels of mRNA encoding type IV collagen correlate well with in situ hybridization studies performed on kidneys expressing early autoimmune lesions, and predict a progressive drop in the expression of type IV collagen in the interstitium. Such a novel and unexpected repression of transcription of type IV collagen might easily impart or facilitate permanent change in the infrastructure of kidney architecture during autoimmune injury and, perhaps, contributes to the process of tubular atrophy attendant to prolonged renal inflammation.

An investigation of the pathophysiology of ischaemic neuropathy

This study assesses the changes in the microvasculature of peripheral nerves in acute large vessel ischaemic neuropathy. An animal model of large vessel ligation, producing an ischaemic neuropathy was used: the presence and extent of the neuropathy was documented by clinical examination and nerve conduction studies. The nerve microcirculation, the "vasa nervorum" was examined using casting materials, methyl methacrylate and silicone rubber, which were in turn examined by light microscopy and scanning electron microscopy. In all, ten animals were used, all of whom showed clinical evidence of an ischaemic neuropathy 1 week post-ligation. This ischaemic neuropathy was confirmed by nerve conduction studies. Corrosion casts were produced in five of the ten animals. Examination of these casts showed that all five had an area of underfilling of the microcirculation in the region of the proximal tibial nerve with good filling of vessels proximal and distal to this, indicating that in generalised hypoperfusion states such as large vessel ligation, the area of poorest perfusion (and thus maximal damage) is not the distal vascular field, but a probable "watershed zone" between two adjacent nutrient vessels to the nerve.

Immunosuppressive mechanisms in protein-calorie malnutrition

Protein-calorie malnutrition (PCM) induces immunosuppression leading to increased mortality rates. Impaired macrophage respiratory burst activity (superoxide anion [O2-] generation) occurs in PCM, but cellular mechanisms are unclear. The major pathway resulting in O2- production involves inositol lipid-dependent signal transduction. This study examined the effect of mild versus severe PCM on macrophage O2- generating signal transduction pathways specific for responses to Candida albicans. Mice (CFW/Swiss Webster: n = 300) were randomized to either control or low protein diets for 3 or 8 weeks. Peritoneal macrophages were harvested for O2- production, mannose-fucose receptor (MFR) expression, membrane phospholipid analysis, arachidonic acid (AA) content, prostaglandin E2 (PGE2) production, and protein kinase C levels. O2- release was impaired in both mild and severe PCM. MFR expression was also decreased at these time points. Inositol lipid content was significantly lower at the 8-week time point only, although PGE2 and AA were significantly higher in the low protein diet group at 3 weeks. Protein kinase C levels were unchanged by PCM. Thus, mild PCM significantly increases macrophage-PGE2 production secondary to increased AA phospholipid content, with subsequent inhibition of O2- and MFR expression. Severe PCM inhibits macrophage (O2-) through depletion of critical membrane phospholipid components with subsequent impairment in signal transduction.

Effector mechanisms in organ-specific autoimmunity. I. Characterization of a CD8+ T cell line that mediates murine interstitial nephritis

To further investigate mechanisms of cell-mediated tissue destruction in an organ-specific autoimmune disease, we have established and characterized a nephritogenic CD8+ T cell line. This target antigen-specific effector T cell line, M52, was derived from bulk populations of CD8+ T cells isolated from susceptible animals immunized to produce anti-tubular basement membrane (alpha TBM) disease. Our studies show that M52 retains the phenotypic and functional characteristics of nephritogenic T cells induced in vivo. M52 mediates antigen-specific delayed-type hypersensitivity (DTH) responses to the target antigen 3M-1, it is cytotoxic to 3M-1-expressing renal tubular epithelial cells in vitro, and it adoptively transfers interstitial nephritis to naive syngeneic recipients. Clonal analysis of these nephritogenic CD8+ T cells reveals distinct functional phenotypes within the M52 cell line. We have isolated a cytotoxic CD8+ clone, M52.26, which is not DTH-reactive to 3M-1, and multiple DTH-reactive clones which mediate less efficient cytotoxicity to 3M-1-expressing target cells. Cytofluorographic analysis of four randomly selected clones reveals alpha beta T cell receptor expression. Further characterization of these functionally distinct CD8+ T cell clones will help to define their respective roles in mediating tubular epithelial cell injury and the inflammatory lesion of autoimmune interstitial nephritis.

Protein-calorie malnutrition impairs host defense against Candida albicans

Protein-calorie malnutrition (PCM) impairs immune responsiveness predisposing to Candida albicans sepsis, but mechanisms are unclear. This study examined the effect of PCM on enteric-derived C. albicans intestinal translocation and the ability of in vivo interferon-gamma (IFN-gamma) to upregulate macrophage (MO) candidacidal mechanisms in PCM mice. Control (24% casein) and low protein (2.5%) diets were given for 4 weeks. Mice (n = 160) were fed C. albicans in their drinking water for 3 days and C. albicans translocation (mean colony-forming units (CFU)/g tissue +/- SEM) to the GI tract, liver, spleen, and kidney was assessed at 1 and 5 days following endotoxin challenge of 1, 5, and 10 mg/kg body wt. In a separate study (n = 100 mice), IFN-gamma (1000-10,000 U/day ip) vs saline was given for 3 days prior to harvesting peritoneal macrophages for assay of superoxide anion (O2-), percentage macrophage phagocytosis of C. albicans, and percentage killing of C. albicans. On Day 1, fungal translocation to the intestinal wall and systemic organs in the PCM group was significantly higher. On Day 5, mean CFU were significantly higher in the PCM group, indicating impaired organ clearance. Mean O2-, phagocytosis, and killing were significantly impaired in the PCM group (P less than 0.05), but IFN-gamma improved all functions. PCM significantly depressed host responses to C. albicans. IFN-gamma treatment enhanced candidacidal mechanisms, suggesting a therapeutic role in the malnourished host predisposed to C. albicans sepsis.

Rat alveolar epithelial cells concomitantly express plasminogen activator inhibitor-1 and urokinase

There is considerable evidence to suggest that intra-alveolar plasminogen activation is instrumental in many aspects of inflammatory lung injury and subsequent tissue repair. Rat alveolar epithelial cells produce large quantities of urokinase-type plasminogen activator (uPA) in vitro, and uPA expression is modulated in association with cellular differentiation and exposure to inflammatory mediators. We now report that these cells also secrete heat-stable PA inhibitory activity having the characteristics of PA inhibitor type 1 (PAI-1). In particular, immunoreactive PAI-1 was demonstrable in conditioned media, cell lysates, and extracellular matrix from epithelial cell cultures. As alveolar epithelial cells differentiated in vitro, secreted PA inhibitor activity increased significantly from 104 +/- PAI U/ml (n = 5, mean +/- SE) on day 2 to 442 +/- 150 on day 7 in parallel with increases in secreted and matrix-associated immunoreactive PAI-1. PAI-1 mRNA expression decreased over this same period suggesting posttranscriptional regulation. The levels of both newly synthesized antigen and PAI-1 mRNA were increased by exposure to lipopolysaccharide and tumor necrosis factor-alpha. Thus, by the coexpression of uPA and PAI-1, the alveolar epithelium may actively regulate the generation of plasmin in both the normal and injured alveolus.

T cell regulation of autoimmune interstitial nephritis

Research in organ-specific autoimmunity has been greatly facilitated over the past decade by advances in cellular and molecular immunology. Such studies have greatly expanded our understanding of autoimmune effector mechanisms and the nature of the target antigens recognized by these mediators. Another facet of organ-specific autoimmunity concerns the definition of those factors that determine host susceptibility to disease. This review outlines studies performed in two models of autoimmune interstitial nephritis that focus on issues of susceptibility and tolerance to parenchymal self antigens. In both models, antigen-specific regulatory T cells modulate the effector limb of the nephritogenic immune response and the pattern of interstitial injury. This modulation can be either stimulatory or inhibitory. The dominant regulatory effect is linked to genes in the major histocompatibility locus and is tightly correlated with disease expression. Regulatory T cells which inhibit the nephritogenic immune response can also be cultured in vitro and are highly efficacious as a therapeutic modality. These studies provide both the background and requisite reagents for delineating the mechanism(s) underlying antigen-specific T cell regulation.

Murine interstitial nephritis. IX. Induction of the nephritogenic effector T cell repertoire with an antigen-specific T cell cytokine

The experiments presented in this report describe the biochemical and functional characteristics of a soluble Th cell factor (ThF) which can induce a nephritogenic effector T cell repertoire producing autoimmune interstitial nephritis. The ThF is Ag-specific, I-A-restricted, and comprises two chains noncovalently linked as a heterodimer. One chain at approximately 78,000 Mr is related to the TCR/Id and expresses a framework determinant (14-30) common to Ag-binding factors, and the other chain at approximately 82,000 Mr is I-A+. Together these chains can replace their parent cell by providing cognate help to precursor effector T lymphocytes in the presence of accessory cells, tubular Ag, and IL-2.

Murine interstitial nephritis. IX. Induction of the nephritogenic effector T cell repertoire with an antigen-specific T cell cytokine

The experiments presented in this report describe the biochemical and functional characteristics of a soluble Th cell factor (ThF) which can induce a nephritogenic effector T cell repertoire producing autoimmune interstitial nephritis. The ThF is Ag-specific, I-A-restricted, and comprises two chains noncovalently linked as a heterodimer. One chain at approximately 78,000 Mr is related to the TCR/Id and expresses a framework determinant (14-30) common to Ag-binding factors, and the other chain at approximately 82,000 Mr is I-A+. Together these chains can replace their parent cell by providing cognate help to precursor effector T lymphocytes in the presence of accessory cells, tubular Ag, and IL-2.

Care of the poor: a story worth telling. A system speaks up and says what it means

Traditionally, those in Catholic healthcare have considered it bad taste to "toot your own horn" for anything done on behalf of the poor. Such reticence was admirable and reasonable in a stable environment, but a turbulent environment requires more assertiveness. Today, healthcare is a whole new game, with new ground rules. It behooves all players to be more critical of all they do, even when "doing good." The Sisters of Charity Health Care Systems (SCHCS), Inc., Cincinnati, established its Task Force for the Poor to explore and initiate new ways to address the needs of the poor, to find strategies for new forms of service, and to develop mechanisms to evaluate those new services and report the results. But with 22 acute care institutions serving different markets in six states, SCHCS had to establish some uniformity to plan, budget, audit, and report the entire spectrum of its charitable activities. The task force proposed developing uniform measures (definitions) of the charity care provided in traditional inpatient and outpatient settings, as well as that provided through services on behalf of the poor but not captured by standard accounting measures.