Crucial role of tumor necrosis factor (TNF) receptor 2 and membrane-bound TNF in experimental cerebral malaria

Tumor necrosis factor (TNF) has been implicated in the pathogenesis of experimental cerebral malaria (CM), but the respective role of its two types of receptors has not been established. A significant increase in the expression of TNF-receptor 2 (TNFR2, p75), but not of TNFR1 (p55), was found on brain microvessels at the time of CM in susceptible animals. Moreover, mice genetically deficient for TNFR2 (Tnfr2null) were significantly protected from experimental CM, in contrast to TNFR1-deficient (Tnfr1null) mice, which were as susceptible as wild-type mice. To identify the factors involved in the protection from CM conferred by the lack of TNFR2, we assessed in both knockout and control mice the serum concentrations of mediators that are critical for the development of CM, as well as the up-regulation of intercellular adhesion molecule-1 (ICAM-1) in the brain microvessels. No significant difference in serum levels of TNF and interferon-gamma was found between infected wild-type and Tnfr1null or Tnfr2null mice. Interestingly, the pronounced ICAM-1 up-regulation and leukocyte sequestration, typically occurring in brain microvessels of CM-susceptible animals, was detected in infected control and Tnfr1null mice-both of which developed CM-whereas no such ICAM-1 up-regulation or leukocyte sequestration was observed in Tnfr2null mice, which were protected from CM. Making use of microvascular endothelium cells (MVEC) isolated from wild-type, Tnfr1null or Tnfr2null mice, we show that soluble TNF requires the presence of both TNF receptors, whereas membrane-bound TNF only needs TNFR2 for TNF-mediated ICAM-1 up-regulation in brain MVEC. Thus, only in MVEC lacking TNFR2, neither membrane-bound nor soluble TNF cause the up-regulation of ICAM-1 in vitro. In conclusion, these results indicate that the interaction between membrane TNF and TNFR2 is crucial in the development of this neurological syndrome.     

Tumor necrosis factor (TNF)-alpha inhibits insulin signaling through stimulation of the p55 TNF receptor and activation of sphingomyelinase

Tumor necrosis factor (TNF)-alpha plays a central role in the state of insulin resistance associated with obesity. It has previously been shown that one important mechanism by which TNF-alpha interferes with insulin signaling is through the serine phosphorylation of insulin receptor substrate-1 (IRS-1), which can then function as an inhibitor of the tyrosine kinase activity of the insulin receptor (IR). However, the receptors and the signaling pathway used by TNF-alpha that mediate the inhibition of IR activity are unknown. We show here that human TNF-alpha, which binds only to the murine p55 TNF receptor (TNFR), is as effective at inhibiting insulin-dependent tyrosine phosphorylation of IR and IRS-1 in adipocytes and myeloid 32D cells as murine TNF-alpha, which binds to both p55 TNFR and p75 TNFR. Likewise, antibodies that are specific agonists for p55 TNFR or p75 TNFR demonstrate that stimulation of p55 TNFR is sufficient to inhibit insulin signaling, though a small effect can also be seen with antibodies to p75 TNFR. Exogenous sphingomyelinase and ceramides, known to be formed by activation of p55 TNFR, inhibit IR and IRS-1 tyrosine phosphorylation and convert IRS-1 into an inhibitor of IR tyrosine kinase in vitro. Myeloid 32D cells expressing IR and IRS-1 are sensitive to this inhibition, but cells expressing IR and IRS-2 are resistant, pointing to an important difference in the biological function between IRS-1 and IRS-2. These data strongly suggest that TNF-alpha inhibits insulin signaling via stimulation of p55 TNFR and sphingomyelinase activity, which results in the production of an inhibitory form of IRS-1.     

Regulation of monocyte chemoattractant protein-1 expression in adult human non-neoplastic astrocytes is sensitive to tumor necrosis factor (TNF) or antibody to the 55-kDa TNF receptor

A trifluoroacetamide analogue of siastatin B, (3S,4S,5R,6R)-6-(trifluoroacetamido)-4,5-dihydroxy-3-piperidine carboxylic acid has been chemically synthesized. This compound, as well as the previously synthesized analogue, (3R,4R,5R,6R)-6-(trifluoroacetamido)-3,4,5-trihydroxy-3-piperid inecarboxylic acid, showed marked inhibitory activity against beta-glucuronidase and significant inhibition of experimental pulmonary metastasis of the highly metastatic melanoma B16.     

Low-molecular-weight tumor necrosis factor receptor p55 controls induction of autoimmune heart disease

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) is involved in the pathogenesis of myocarditis and can bind to either tumor necrosis factor receptor (TNF-R) p55 or TNF-Rp75. However, it is not known which TNF-R mediates the specific functions of TNF in disease. To determine the role of the TNF/TNF-R system in chronic heart disease, we used a murine model of cardiac myosin-induced myocarditis that closely resembles the chronic stages of virus-induced myocarditis in humans. METHODS AND RESULTS: Mice lacking TNF-Rp55 expression after targeted disruption of the TNF-Rp55 gene were backcrossed into a genetic background susceptible to the induction of myocarditis with cardiac myosin. Here, we demonstrate that TNF-Rp55 gene-deficient mice did not develop any inflammatory infiltration into the heart after autoantigen injection, whereas control littermates showed autoimmune myocarditis at high prevalence and severity. Despite the absence of autoimmune heart disease, TNF-Rp55-/- mice produced cardiac myosin-specific IgG autoantibodies, indicating that activation of autoaggressive T and B lymphocytes had occurred. However, heart interstitial cells failed to express major histocompatibility complex (MHC) class II molecules in TNF-Rp55-/- animals, and adoptive transfer of autoreactive T cells resulted in heart disease only in TNF-Rp55-/- but not in TNF-Rp55-/- littermates. CONCLUSIONS: Cardiac myosin-induced myocarditis is dependent on autoaggressive T cells and on autoantigen presentation in association with MHC class II molecules within the heart. Thus, lack of TNF-Rp55 expression could interfere with either lymphocyte activation or target organ susceptibility. The data presented here show that the TNF-Rp55 is a key regulator for the induction of autoimmune heart disease by its controlling target organ susceptibility.     

Efficient, repeated adenovirus-mediated gene transfer in mice lacking both tumor necrosis factor alpha and lymphotoxin alpha

The efficiency of adenovirus-mediated gene transfer is now well established. However, the cellular and the humoral immune responses triggered by vector injection lead to the rapid elimination of the transduced cells and preclude any efficient readministration. The present investigation focuses on the role of tumor necrosis factor alpha (TNF-alpha), a proinflammatory cytokine, and the related cytokine lymphotoxin alpha (LTalpha), in mounting an immune reaction against recombinant adenovirus vectors. After gene transfer in the liver, mice genetically deficient for both cytokines (TNF-alpha/LTalpha-/-), in comparison with normal mice, presented a weak acute-phase inflammatory reaction, a reduction in cellular infiltrates in the liver, and a severely impaired T-cell proliferative response to both Adenoviral and transgene product antigens. Moreover, we observed a strong reduction in the humoral response to the vector and the transgene product, with a drastic reduction of anti-adenovirus immunoglobulin A and G antibody isotypes. In addition, the reduction in antibody response observed in TNF-alpha/LTalpha-/- and TNF-alpha/LTalpha+/- mice versus TNF-alpha/LTalpha+/+ mice links antibody levels to TNF-alpha/LTalpha gene dosage. Due to the absence of neutralizing antibodies, the TNF-alpha/LTalpha knockout mice successfully express a second gene transduced by a second vector injection. The discovery of the pivotal role played by TNF-alpha in controlling the antibody response against adenovirus will allow more efficient adenovirus-based strategies for gene therapy to be proposed.     

Soluble tumor necrosis factor receptor (p75) fusion protein (ENBREL) as a therapy for rheumatoid arthritis

Soluble tumor necrosis factor (TNF) receptor fusion protein (p75) (Enbrel) is a reversible inhibitor of the biologic effects of TNF. Enbrel has been shown in placebo-controlled trials to significantly improve the signs and symptoms of rheumatoid arthritis. Clinical trials are now in progress to assess the safety and efficacy of Enbrel in combination with methotrexate in refractory rheumatoid arthritis along with trials to compare Enbrel to methotrexate in patients with early rheumatoid arthritis.     

TNF receptor-deficient mice reveal divergent roles for p55 and p75 in several models of inflammation

The pleiotropic activities of the potent proinflammatory cytokine TNF are mediated by two structurally related, but functionally distinct, receptors, p55 and p75, that are coexpressed on most cell types. The majority of biologic responses classically attributed to TNF are mediated by p55. In contrast, p75 has been proposed to function as both a TNF antagonist by neutralizing TNF and as a TNF agonist by facilitating the interaction between TNF and p55 at the cell surface. We have examined the roles of p55 and p75 in mediating and modulating the activity of TNF in vivo by generating and examining mice genetically deficient in these receptors. Selective deficits in several host defense and inflammatory responses are observed in mice lacking p55 or both p55 and p75, but not in mice lacking p75. In these models, the activity of p55 is not impaired by the absence of p75, arguing against a physiologic role for p75 as an essential element of p55-mediated signaling. In contrast, exacerbated pulmonary inflammation and dramatically increased endotoxin induced serum TNF levels in mice lacking p75 suggest a dominant role for p75 in suppressing TNF-mediated inflammatory responses. In summary, these data help clarify the biologic roles of p55 and p75 in mediating and modulating the biologic activity of TNF and provide genetic evidence for an antagonistic role of p75 in vivo.     

An apoptosis-inducing gene therapy for pancreatic cancer with a combination of 55-kDa tumor necrosis factor (TNF) receptor gene transfection and mutein TNF administration

Intratumoral injection of recombinant human tumor necrosis factor (TNF) for inoperable pancreatic cancer has shown some efficacy in suppressing tumor growth or decreasing tumor markers. However, complete regression has not yet been achieved, possibly due to a lack of TNF receptors on tumor cells or an abundance of intracellular resistance factors. Recently, two distinct types of TNF receptors, R55 and R75, were identified, which are responsible for signaling of cytotoxicity and of proinflammation, respectively. In this study, a novel type of suicide gene therapy is proposed that is based on transfection of the R55 gene into human pancreatic cancer cells (AsPC-1 and PANC-1) and subsequent administration of TNF. The transfectants from both cell lines showed higher TNF susceptibility than their parental cells. In vivo tumor formation of an AsPC-1 clone (clone 10) inoculated in nude mice was substantially suppressed by administration of TNF. For practical use of this strategy, however, the adverse effects of TNF may become an obstacle. We previously produced mutein TNF 471, which had a higher affinity for R55, superior antitumor activity, and fewer adverse effects. This mutein TNF 471 manifested greater antitumor activity against clone 10. Because the R55 receptor is known to be involved in augmentation of cellular immunity by TNF, mutein TNF 471 is also expected to be highly potent in this function. In fact, the mutein TNF 471 induced higher splenic natural killer cell activity in nude mice inoculated with clone 10 than did native TNF. This property of augumenting cellular responses may be advantageous in the eradication of viable tumor cells left untransfected in practical gene therapy regimens in which 100% transfection of the R55 gene into tumors is not feasible. Thus, gene therapy combining transfection of the TNF-R55 gene with administration of mutein TNF 471 may provide a new modality for the treatment of pancreatic cancer.     

Dimerization of chimeric erythropoietin/75 kDa tumour necrosis factor (TNF) receptors transduces TNF signals: necessity for the 75 kDa-TNF receptor transmembrane domain

We developed a transfection-based assay for evaluating human (h) Tumour Necrosis Factor receptor (TNF-R) activities in a rat/mouse T-cell hybridoma, viz. PC60. Here we report on the role of TNF-R75 cross-linking in induction of GM-CSF secretion and apoptosis. The effect of TNF-R75 dimerization, in contrast to trimerization, was analysed by replacing the extracellular domain of this receptor with the equivalent domain of the murine erythropoietin receptor (EPO-R), which dimerizes upon ligand interaction. To determine the role of the transmembrane region in signal transduction, chimeric EPO-R/TNF-R75 were constructed in which the respective transmembrane domains were interchanged. The hybrid receptors were introduced into PC60hTNFR55 cells, which already expressed functional, transfected hTNF-R55. By this approach we demonstrated that dimerized chimeric EPO-R/TNF-R75 receptors act synergistically with hTNF-R55-induced cytokine production and apoptosis as does trimerized wild-type hTNF-R75. Dimeric triggering of these hybrid receptors with EPO alone was less efficient than trimerization of hTNF-R75. Furthermore, EPO-R/TNFR75 only responded to EPO when the matching transmembrane region of TNF-R75 was present. Our results also prove that the hTNF-R75 extracellular part per se is not required for signalling. Finally, our data indicate that the expression of chimeric EPO-R/TNF-R75 in PC60hTNF-R55 cells, regardless of the presence of the TNF-R75 transmembrane region, facilitates TNF-R55-dependent signal transduction leading to apoptosis. This means that introduction of the intracellular domain of hTNF-R75, even without triggering, is sufficient to promote hTNF-R55-dependent activities in PC60 cells.     

TNF-induced superoxide anion production in adherent human neutrophils involves both the p55 and p75 TNF receptor

TNF, a potent activator of neutrophil granulocytes, acts via two cell-surface receptors: the p55-TNF receptor (TNF-R55) and the p75-TNF receptor (TNF-R75), which can be cleaved from the cell surface and thus form soluble TNF-binding proteins (TNF-BP). The role of the two receptors in activation of the neutrophil respiratory burst was investigated. Two mAbs reacting with TNF-R55 (H398 and TBP2) induced O2 release in a similar manner but to a lesser extent than TNF. TBP2, however, required preincubation at 4 degrees C to exert its effect. Preincubation of neutrophils (both at 4 and 37 degrees C) with mAb to TNF-R75 decreased TNF-induced superoxide anion production by 67 and 64%, respectively, indicating the essential role also for TNF-R75 in neutrophil activation. This inhibitory effect could not be explained by cross-down-regulation of TNF-R55 because the TNF-R75 mAb had no effect on TNF binding to TNF-R55 as determined by binding of 125I-labeled TNF or release of TNF-R55-BP as measured by ELISA. Furthermore, the TNF-R75 mAb did not decrease superoxide anion generation induced by the TNF-R55 mAb H398, thus ruling out that the inhibitory effect of the TNF-R75 mAb is due to inhibition of the signaling pathway downstream of TNF-R55. In contrast to the TNF-R75 mAb, TNF-R55 mAbs induced down-regulation of TNF-R75 and shedding of both TNF-R55-BP and TNF-R75-BP. We conclude that both TNF-R55 and TNF-R75 are involved in TNF-induced activation of the neutrophil respiratory burst.     

Neuronal-associated tumor necrosis factor (TNF alpha): its role in noradrenergic functioning and modification of its expression following antidepressant drug administration

Because of its wide variety of symptoms, the neurovascular compression syndrome of the upper thoracic aperture or thoracic outlet syndrome (TOS) has to be distinguished from several differential diagnoses, especially orthopedic ones. It is mainly characterized by pressure lesion of the brachial plexus and secondly, by accompanying vascular damages. An indication for surgery exists in cases of persisting or increasing complaints or function loss of shoulder, arm or hand muscles as well as in cases with occurrence of vascular damage. The treatment of choice consists of transaxillary resection of the first rib. This report presents a record of our results after transaxillary surgery and compares them to the results given in current international literature. During the last few years 3031 cases of transaxillary resections (13-473 cases) were described in international literature. The average follow-up period was 7.8 years (2-22 years). The results were good in 81.4% (50-93%) of the cases. From 02/80 to 03/94, we treated 67 patients with altogether 80 thoracic outlet syndromes (TOS). Each of them was treated similarly with extensive transaxillary resection of the first rib, excision of fibrous bands and, if necessary, of cervical ribs. Our results after surgery (84.5% of complete resolution or improvement of symptoms) compare favorably to those given by other authors. The average follow-up period was 6.6 years (0.5-14 years). Our results confirm, that transaxillary resection of the first rib is the method of choice in the treatment of thoracic outlet syndromes.     

Enhancement of the surface expression of tumor necrosis factor alpha (TNFalpha) but not the p55 TNFalpha receptor in the THP-1 monocytic cell line by matrix metalloprotease inhibitors

The monocytic cell line THP-1 can be induced to express and release tumor necrosis factor alpha (TNFalpha) and both TNFalpha receptors (p55 and p75) upon exposure to bacterial lipopolysaccharide (LPS). The broad-spectrum matrix metalloprotease (MMP) inhibitors [4-(N-hydroxyamino)-2R-isobutyl-3S-(phenylthiomethyl)succinyl]-L-p henylalanine-N-methylamide (GI-129471) and marimastat [2S-[N4(R*),2R*,3S*]]-N4[2,2-dimethyl-1-[(methylamino)carbonyl]propyl]-N 1,2-dihydroxy-3-(2-methylpropyl)butanediamide (BB-2516) were effective inhibitors of LPS-induced TNFalpha (soluble) release with IC50 values of 0.2 and 4.0 microM, respectively. Upon LPS stimulation, the expression of pro-TNFalpha (membrane associated) on the cell surface (FACS analysis) could not be observed. However, in the presence of GI-129471, a concentration-dependent increase in TNFalpha surface expression was observed. Peak expression (percentage of cells expressing pro-TNFalpha and mean fluorescence units) in the presence of GI-129471 was at 2 hr, and steadily declined to return to near control levels by 8 hr. This time course was similar to TNFalpha release, which also peaked at 2-4 hr after LPS exposure and then declined. Stimulation of THP-1 cells with LPS + phorbol myristate acetate increased the percentage of cells expressing pro-TNFalpha by 10-fold. In the presence of GI-129471, these increases were augmented further and peaked between 2 and 4 hr, but also returned to near control levels of expression by 24 hr. This was in contrast to the release of soluble TNFalpha, which continued to accumulate over a 24-hr time course. TNFalpha receptor I (p55, TNFRI) and II (p75, TNFRII) shedding was also inhibited by GI-129471 (IC50 = 1.5 and 3.1 microM, respectively) and BB-2516 (IC50 = 14 and 15 microM, respectively). Unlike pro-TNFalpha surface expression, surface expression of both TNFalpha receptors steadily increased over 72 hr. In contrast to pro-TNFalpha surface expression, TNFRI surface expression was not augmented by these MMP inhibitors in THP-1 cells after LPS stimulation. Surface expression of TNFRII was augmented by these MMP inhibitors. These results suggest that even in the continued presence of LPS stimulation and an inhibitor of TNFalpha processing, the augmented surface expression of TNFalpha is transient. The potential "deleterious" implications of high levels of surface pro-TNFalpha expression in the presence of these inhibitors may be lessened by its transient nature.     

The local role of tumor necrosis factor alpha in the modulation of neutrophil function at sites of inflammation

OBJECTIVE: To examine the hypothesis that tumor necrosis factor alpha (TNF-alpha) is an important local modulator of neutrophil function in the inflammatory microenvironment. DESIGN: In vitro studies of host defense. PATIENTS: A volunteer sample of healthy subjects. INTERVENTION: Exudative neutrophils were collected from skin-blister chambers and functionally compared with blood neutrophils. METHODS: Tumor necrosis factor alpha levels at sites of inflammation and neutrophil exudation were determined and compared with serum concentrations. Flow cytometry was used to evaluate neutrophil microbicidal activity and N-formyl-methionyl-leucyl-phenylalanine-induced changes in intracellular calcium and superoxide production. In vitro TNF-alpha was used to evaluate the nature and dose response of TNF-alpha-induced changes in neutrophil function. RESULTS: Exudative neutrophils have an increased responsiveness to subsequent N-formyl-methionyl-leucyl-phenylalanine stimulation, as determined by changes in intracellular calcium. Microbicidal activity and superoxide production are also up-regulated compared with circulating neutrophils. The exudative microenvironment contains TNF-alpha at local levels that are capable of significantly enhancing neutrophil host defense. CONCLUSIONS: Tumor necrosis factor alpha may serve to enhance neutrophil function at sites of inflammation. Neutrophils become more cytotoxic and have an enhanced ability to respond to weak environmental signals.     

Distinct domains of M-T2, the myxoma virus tumor necrosis factor (TNF) receptor homolog, mediate extracellular TNF binding and intracellular apoptosis inhibition

The myxoma virus tumor necrosis factor (TNF) receptor homolog, M-T2, is expressed both as a secreted glycoprotein that inhibits the cytolytic activity of rabbit TNF-alpha and as an endoglycosidase H-sensitive intracellular species that prevents myxoma virus-infected CD4+ T lymphocytes from undergoing apoptosis. To compare the domains of M-T2 mediating extracellular TNF inhibition and intracellular apoptosis inhibition, recombinant myxoma viruses expressing nested C-terminal truncations of M-T2 protein were constructed. One mutant, deltaL113, containing intact copies of only two cysteine-rich domains, was not secreted and was incapable of binding rabbit TNF-alpha yet retained full ability to inhibit virus-induced apoptosis of RL-5 cells. Thus, the minimal domain of intracellular M-T2 protein required to inhibit apoptosis is distinct from that required by the extracellular M-T2 for functional TNF-alpha binding and inhibition. This is the first report of a virus-encoded immunomodular protein with two distinct antiimmune properties.     

A role for tumor necrosis factor receptor type 1 in gut-associated lymphoid tissue development: genetic evidence of synergism with lymphotoxin beta

Lymphotoxin alpha (LTalpha) signals via tumor necrosis factor receptors (TNFRs) as a homotrimer and via lymphotoxin beta receptor (LTbetaR) as a heterotrimeric LTalpha1beta2 complex. LTalpha-deficient mice lack all lymph nodes (LNs) and Peyer's patches (PPs), and yet LTbeta-deficient mice and TNFR-deficient mice have cervical and mesenteric LN. We now show that mice made deficient in both LTbeta and TNFR type 1 (TNFR1) lack all LNs, revealing redundancy or synergism between TNFR1 and LTbeta, acting presumably via LTbetaR. A complete lack of only PPs in mice heterozygous for both ltalpha and ltbeta, but not ltalpha or ltbeta alone, suggests a similar two-ligand phenomenon in PP development and may explain the incomplete lack of PPs seen in tnfr1-/- mice.     

Distinct adapter proteins mediate acid versus neutral sphingomyelinase activation through the p55 receptor for tumor necrosis factor

Ceramide, generated by the enzymatic function of sphingomyelinases (SMases) has emerged as an important signaling pathway transducing diverse biological effects of various cytokine receptors. The 55-kDa receptor for tumor necrosis factor (TNF-R55) activates two types of SMases through distinct cytoplasmic domains. The death domain that is responsible for the initiation of the apoptotic pathway also signals for the activation of an acid SMase (A-SMase). The adapter protein TRADD binds to TNF-R55 in a ligand-dependent manner and serves as anchor for the subsequent recruitment of other proteins into the signaling complex that directly lead to cell death or nuclear factor-kappaB (NF-kappaB) induction. Notably, the two pro-apoptotic adapter proteins TRADD and FADD are also involved in the activation of A-SMase. In contrast, the NF-kappaB-inducing adapters TRAF2 and RIP do not signal for A-SMase. Thus, activation of A-SMase appears to belong to signals leading to TNF-induced cell death. A second signaling domain (NSD) is located upstream of the death domain and directly links the TNF-R55 to the activation of a neutral SMase (N-SMase). A novel adapter protein, FAN, has been identified that specifically binds to the NSD. FAN contains five WD repeats at its carboxy terminus, while it shows significant sequence homology with the mouse beige protein and its human homolog, the CHS protein, in the center portion of the protein. Overexpression of full-length FAN enhanced N-SMase activity in TNF-treated cells, whereas truncated mutants of FAN produced dominant negative effects. FAN, however, did not interfere with any of the TNF responses signaled for by the death domain. Taken together, our data suggest that distinct cytoplasmic domains of TNF-R55 initiate independent signaling pathways by binding different adapter proteins.     

Prevention of autoimmune diabetes mellitus in NOD mice by transgenic expression of soluble tumor necrosis factor receptor p55

The non-obese diabetic (NOD) mouse represents a relevant animal model of autoimmunity for insulin-dependent diabetes mellitus. The pathogenic role of tumor necrosis factor (TNF) in insulitis and beta cell destruction observed in these mice remains controversial, since injections of TNF or of anti-TNF antibodies have been reported to exert protection or acceleration of diabetes, depending on the timing of administration. In this study, we demonstrate that, in contrast to the non-transgenic littermates, NOD mice with permanent neutralization of TNF by high blood levels of soluble TNF receptor p55-human FcIgG3-fusion molecules resulting from the expression of a transgene are protected from spontaneous diabetes. They are also protected from accelerated forms of disease caused by transfer of NOD spleen cells or cyclophosphamide injections. This protection is associated with a marked decrease in the severity and incidence of insulitis and in the expression of the adhesion molecules MAdCAM-1 and ICAM-1 on the venules of pancreatic islets. These data suggest a central role for TNF-alpha in the mediation of insulitis and of the subsequent destruction of insulin-secreting beta-cells observed in NOD mice. They may be relevant to cell-mediated autoimmune diseases in general, in which treatment with soluble TNF receptors might be beneficial.     

A highly polymorphic CA repeat marker at the human tumor necrosis factor alpha (TNFA alpha) locus

A case of partial bone necrosis of the articular tubercle of the temporomandibular joint is presented. It was probably caused by repeated injections of sodium hyaluronate in the joint. A sequestrectomy was performed under general anesthesia, and the postoperative course was uneventful.