Formation and inactivation of endogenous cannabinoid anandamide in central neurons

Anandamide (N-arachidonoyl-ethanolamine) was recently identified as a brain arachidonate derivative that binds to and activates cannabinoid receptors, yet the mechanisms underlying formation, release and inactivation of this putative messenger molecule are still unclear. Here we report that anandamide is produced in and released from cultured brain neurons in a calcium ion-dependent manner when the neurons are stimulated with membrane-depolarizing agents. Anandamide formation occurs through phosphodiesterase-mediated cleavage of a novel phospholipid precursor, N-arachidonoyl-phosphatidylethanolamine. A similar mechanism also governs the formation of a family of anandamide congeners, whose possible roles in neuronal signalling remain unknown. Our results and those of others indicate therefore that multiple biochemical pathways may participate in anandamide formation in brain tissue. The life span of extracellular anandamide is limited by a rapid and selective process of cellular uptake, which is accompanied by hydrolytic degradation to ethanolamine and arachidonate. Our results thus strongly support the proposed role of anandamide as an endogenous neuronal messenger.

Melanoma cell expression of Fas(Apo-1/CD95) ligand: implications for tumor immune escape

Malignant melanoma accounts for most of the increasing mortality from skin cancer. Melanoma cells were found to express Fas (also called Apo-1 or CD95) ligand (FasL). In metastatic lesions, Fas-expressing T cell infiltrates were proximal to FasL+ tumor cells. In vitro, apoptosis of Fas-sensitive target cells occurred upon incubation with melanoma tumor cells; and in vivo, injection of FasL+ mouse melanoma cells in mice led to rapid tumor formation. In contrast, tumorigenesis was delayed in Fas-deficient lpr mutant mice in which immune effector cells cannot be killed by FasL. Thus, FasL may contribute to the immune privilege of tumors.

Astrocytes present myelin basic protein to encephalitogenic T-cell lines

Astrocyte proliferation and perivascular lymphocyte infiltration are conspicuous among the cellular changes in the active brain lesions of multiple sclerosis patients. Recent observations have indicated that most of the perivascular lymphocytes are T cells which may be actively involved in the generation of the brain lesions. Much less is known about the significance of the proliferative astrocytes, although the fact that they produce an interleukin-1 (IL-1)-like factor that enhances the release of interleukin-2 by T lymphocytes, may provide a clue. We show here that rat astrocytes are able to present antigen to T lymphocytes in a specific manner which is restricted by the major histocompatibility complex (MHC) and that they can in particular activate myelin basic protein (BP)-specific, encephalitogenic T-cell lines. Only on such interaction do astrocytes express Ia antigens in easily detectable amounts. Antigen presentation by astrocytes may have a central role in the generation of immune responses in the brain.

Conversion of membrane-bound Fas(CD95) ligand to its soluble form is associated with downregulation of its proapoptotic activity and loss of liver toxicity

Human Fas ligand (L) (CD95L) and tumor necrosis factor (TNF)-alpha undergo metalloproteinase-mediated proteolytic processing in their extracellular domains resulting in the release of soluble trimeric ligands (soluble [s]FasL, sTNF-alpha) which, in the case of sFasL, is thought to be implicated in diseases such as hepatitis and AIDS. Here we show that the processing of sFasL occurs between Ser126 and Leu127. The apoptotic-inducing capacity of naturally processed sFasL was reduced by >1,000-fold compared with membrane-bound FasL, and injection of high doses of recombinant sFasL in mice did not induce liver failure. However, soluble FasL retained its capacity to interact with Fas, and restoration of its cytotoxic activity was achieved both in vitro and in vivo with the addition of cross-linking antibodies. Similarly, the marginal apoptotic activity of recombinant soluble TNF-related apoptosis-inducing ligand (sTRAIL), another member of the TNF ligand family, was greatly increased upon cross-linking. These results indicate that the mere trimerization of the Fas and TRAIL receptors may not be sufficient to trigger death signals. Thus, the observation that sFasL is less cytotoxic than membrane-bound FasL may explain why in certain types of cancer, systemic tissue damage is not detected, even though the levels of circulating sFasL are high.

On the cellular source and function of interleukin 6 produced in the central nervous system in viral diseases

Interleukin 6 (IL6) was found to be produced in the central nervous system (CNS) of ICR+/+ mice infected with lymphocytic choriomeningitis virus (LCMV) or with vesicular stomatitis virus (VSV). When infecting athymic ICR nu/nu mice which cannot develop T cell-mediated meningitis after LCMV infection, no significant synthesis of IL6 was detected in the CNS. IL6 was found, however, to be produced intrathecally in ICR nu/nu mice infected with VSV, which causes a T cell-independent acute encephalitis. This suggested that IL6 may also originate from cells not belonging to the T cell compartment. Indeed, in vitro assays showed that both virus-infected microglial cells and astrocytes secreted IL6. In astrocytes, the infection resulted in the induction of the 1.3-kb messenger RNA IL6. Besides its effect on the development of B cell immunity in the brain, IL6 may be involved in repair mechanisms initiated in the course of viral-induced tissue damage. As shown here, IL6 induced an increase of the secretion of a neurotrophic factor, nerve growth factor by astrocytes. Thus, the intrathecal synthesis of IL6 may be part of the host response to infection favoring immune-mediated elimination of the infectious agent as well as trophic support for neurons.

Accuracy of clinical diagnosis of Parkinson disease: A systematic review and meta-analysis

OBJECTIVE

To evaluate the diagnostic accuracy of clinical diagnosis of Parkinson disease (PD) reported in the last 25 years by a systematic review and meta-analysis.

METHODS

We searched for articles published between 1988 and August 2014. Studies were included if reporting diagnostic parameters regarding clinical diagnosis of PD or crude data. The selected studies were subclassified based on different study setting, type of test diagnosis, and gold standard. Bayesian meta-analyses of available data were performed.

RESULTS

We selected 20 studies, including 11 using pathologic examination as gold standard. Considering only these 11 studies, the pooled diagnostic accuracy was 80.6% (95% credible interval [CrI] 75.2%-85.3%). Accuracy was 73.8% (95% CrI 67.8%-79.6%) for clinical diagnosis performed mainly by nonexperts. Accuracy of clinical diagnosis performed by movement disorders experts rose from 79.6% (95% CrI 46%-95.1%) of initial assessment to 83.9% (95% CrI 69.7%-92.6%) of refined diagnosis after follow-up. Using UK Parkinson's Disease Society Brain Bank Research Center criteria, the pooled diagnostic accuracy was 82.7% (95% CrI 62.6%-93%).

CONCLUSION

The overall validity of clinical diagnosis of PD is not satisfying. The accuracy did not significantly improve in the last 25 years, particularly in the early stages of disease, where response to dopaminergic treatment is less defined and hallmarks of alternative diagnoses such as atypical parkinsonism may not have emerged. Misclassification rate should be considered to calculate the sample size both in observational studies and randomized controlled trials. Imaging and biomarkers are urgently needed to improve the accuracy of clinical diagnosis in vivo.

Antigen presentation and tumor cytotoxicity by interferon-gamma-treated microglial cells

In this study microglial cells isolated from brain cell cultures of newborn mice were characterized and investigated for morphology, their responses to growth factors and their functional properties. The microglial cells were phagocytic, contained nonspecific esterase activity and expressed Fc (IgG1/2b) and type-3 complement receptors. Scanning electron microscopy revealed that in analogy to brain tissue two types of microglial cells are present in the cultures: the ameboid and the ramified type which both display similar appearance by transmission electron microscopy. Interleukin 3 and the granulocyte-macrophage colony-stimulating factor were potent growth factors for the cultured microglial cells. The cells were negative for class II antigens (Ia) of the major histocompatibility antigen complex. However, upon treatment with interferon-gamma (IFN-gamma) microglial cells became Ia+ and functioned as antigen-presenting cells when tested on ovalbumin-specific Ia-restricted helper T cells. Furthermore, microglial cells exposed to IFN-gamma and endotoxin developed tumor cell cytotoxicity and produced tumor necrosis factor alpha. Taken together, microglial cells share the characteristics of cells of the macrophage lineage.

Prevention of islet allograft rejection with engineered myoblasts expressing FasL in mice

Allogeneic transplantation of islets of Langerhans was facilitated by the cotransplantation of syngeneic myoblasts genetically engineered to express the Fas ligand (FasL). Composite grafting of allogeneic islets with syngeneic myoblasts expressing FasL protected the islet graft from immune rejection and maintained normoglycemia for more than 80 days in mice with streptozotocin-induced diabetes. Graft survival was not prolonged with composite grafts of unmodified myoblasts or Fas-expressing myoblasts. Islet allografts transplanted separately from FasL-expressing myoblasts into the contralateral kidney were rejected, as were similarly transplanted third-party thyroid allografts. Thus, the FasL signal provided site- and immune-specific protection of islet allografts.

Murine brain macrophages induced NMDA receptor mediated neurotoxicity in vitro by secreting glutamate

Supernatants (SN) of brain macrophages in culture induce death of cerebellar granule cells in vitro, while those of astrocytes and endothelial cells do not. This toxicity can be prevented by N-methyl-D-aspartate (NMDA) receptor antagonists. Macrophage SN contain high concentrations of glutamate. Reducing the glutamate level of macrophage SN, either by exposure to astrocytes or by enzymatic degradation abolished the toxic effect. Thus, macrophage neurotoxicity is mediated by glutamate acting on NMDA receptors, and might play a role in vivo in traumatic and cerebrovascular brain lesions.

Old galaxies in the young Universe

More than half of all stars in the local Universe are found in massive spheroidal galaxies, which are characterized by old stellar populations with little or no current star formation. In present models, such galaxies appear rather late in the history of the Universe as the culmination of a hierarchical merging process, in which larger galaxies are assembled through mergers of smaller precursor galaxies. But observations have not yet established how, or even when, the massive spheroidals formed, nor if their seemingly sudden appearance when the Universe was about half its present age (at redshift z approximately 1) results from a real evolutionary effect (such as a peak of mergers) or from the observational difficulty of identifying them at earlier epochs. Here we report the spectroscopic and morphological identification of four old, fully assembled, massive (10(11) solar masses) spheroidal galaxies at l.6 < z < 1.9, the most distant such objects currently known. The existence of such systems when the Universe was only about one-quarter of its present age shows that the build-up of massive early-type galaxies was much faster in the early Universe than has been expected from theoretical simulations.

Anti-Fas/APO-1 antibody-mediated apoptosis of cultured human glioma cells. Induction and modulation of sensitivity by cytokines

Fas/APO-1 is a transmembrane protein of the nerve growth factor/TNF alpha receptor family which signals apoptotic cell death in susceptible target cells. We have investigated the susceptibility of seven human malignant glioma cell lines to Fas/APO-1-dependent apoptosis. Sensitivity to Fas/APO-1 antibody-mediated cell killing correlated with cell surface expression of Fas/APO-1. Expression of Fas/APO-1 as well as Fas/APO-1-dependent cytotoxicity were augmented by preexposure of human malignant glioma cells to IFN gamma and TNF alpha. Further, pretreatment with TGF beta 2, IL1 and IL8 enhanced Fas/APO-1 antibody-induced glioma cell apoptosis whereas other cytokines including TNF beta, IL6, macrophage colony-stimulating factor, IL10 and IL13 had no such effect. None of the human malignant glioma cell lines was susceptible to TNF alpha-induced cytotoxicity. Fas/APO-1 antibody-sensitive glioma cell lines (n = 5), but not Fas/APO-1 antibody-resistant glioma cell lines (n = 2), became sensitive to TNF alpha when co-treated with inhibitors of RNA and protein synthesis. Resistance of human glioma cells to Fas/APO-1 antibody-mediated apoptosis was mainly related to low level expression of Fas/APO-1 and appeared not to be linked to overexpression of the anti-apoptotic protooncogene, bcl-2. Given the resistance of human malignant glioma to surgery, irradiation, chemotherapy and immunotherapy, we propose that Fas/APO-1 may be a promising target for a novel locoregionary approach to human malignant glioma. This strategy gains support from the demonstration of Fas/APO-1 expression in ex vivo human malignant glioma specimens and from the absence of Fas/APO-1 in normal human brain parenchyma.

Glucose induces beta-cell apoptosis via upregulation of the Fas receptor in human islets

In autoimmune type 1 diabetes, Fas-to-Fas-ligand (FasL) interaction may represent one of the essential pro-apoptotic pathways leading to a loss of pancreatic beta-cells. In the advanced stages of type 2 diabetes, a decline in beta-cell mass is also observed, but its mechanism is not known. Human islets normally express FasL but not the Fas receptor. We observed upregulation of Fas in beta-cells of type 2 diabetic patients relative to nondiabetic control subjects. In vitro exposure of islets from nondiabetic organ donors to high glucose levels induced Fas expression, caspase-8 and -3 activation, and beta-cell apoptosis. The effect of glucose was blocked by an antagonistic anti-Fas antibody, indicating that glucose-induced apoptosis is due to interaction between the constitutively expressed FasL and the upregulated Fas. These results support a new role for glucose in regulating Fas expression in human beta-cells. Upregulation of the Fas receptor by elevated glucose levels may contribute to beta-cell destruction by the constitutively expressed FasL independent of an autoimmune reaction, thus providing a link between type 1 and type 2 diabetes.

Activation of Fas by FasL induces apoptosis by a mechanism that cannot be blocked by Bcl-2 or Bcl-x(L)

Fas activation triggers apoptosis in many cell types. Studies with anti-Fas antibodies have produced conflicting results on Fas signaling, particularly the role of the Bcl-2 family in this process. Comparison between physiological ligand and anti-Fas antibodies revealed that only extensive Fas aggregation, by membrane bound FasL or aggregated soluble FasL consistently triggered apoptosis, whereas antibodies could act as death agonists or antagonists. Studies on Fas signaling in cell lines and primary cells from transgenic mice revealed that FADD/MORT1 and caspase-8 were required for apoptosis. In contrast, Bcl-2 or Bcl-x(L) did not block FasL-induced apoptosis in lymphocytes or hepatocytes, demonstrating that signaling for cell death induced by Fas and the pathways to apoptosis regulated by the Bcl-2 family are distinct.

Correlation between sites of limited proteolysis and segmental mobility in thermolysin

Limited proteolysis or autolysis of thermolysin under different experimental conditions leads to fission of a small number of peptide bonds located in exposed surface segments of the polypeptide chain characterized by highest mobility, as given by the temperature factors (B values) determined crystallographically [Holmes, M.A., & Matthews, B.W. (1982) J. Mol. Biol. 160, 623-639]. Considering also similar findings observed previously with other protein systems, it is proposed that this correlation between segmental mobility and sites of limited proteolysis in globular proteins is quite general. Thus, flexibility of the polypeptide chain of a globular protein at the site of proteolytic attack promotes optimal binding and proper interaction with the active site of the protease. These findings emphasize that apparent thermal motion seen in protein crystals is relevant to motion in solution and appear to be of general significance in protein-protein recognition processes.

IL-6-deficient mice resist myelin oligodendrocyte glycoprotein-induced autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is induced by immunization with myelin components including myelin oligodendrocyte glycoprotein (MOG). Myelin-specific Th1 cells enter the central nervous system (CNS) via binding of very late antigen 4 (VLA-4) to the endothelial vascular cell adhesion molecule 1 (VCAM-1). In the present study, mice with a homologous disruption of the gene encoding IL-6 are found to be resistant to MOG-induced EAE as evidenced by absence of clinical symptoms, minimal infiltration of CD3+ T cells and monocytes into the CNS and lack of demyelination. The failure to induce EAE in IL-6-/- mice is not due to the absence of priming, since lymphocytes of immunized IL-6-/- mice proliferate in response to MOG and produce pro-inflammatory cytokines including IL-2 and IFN-gamma. However, in MOG-immunized IL-6-/- mice, serum anti-MOG antibody titers were found to be drastically reduced. This observation is unlikely to be responsible for resistance to EAE, because B cell-deficient (microMT) mice proved to be fully susceptible to the disease. A striking difference between MOG-immunized wild-type (wt) and IL-6-/- mice was the expression of endothelial VCAM-1 and ICAM-1, which were dramatically up-regulated in the CNS in wt but not in IL-6-/- mice. Taking into account recent studies on the role of VCAM-1 in the entry of Th1 cells into the CNS, the absence of VCAM-1 on endothelial cells in IL-6-/- mice may explain their resistance to EAE.

The antidepressant rolipram suppresses cytokine production and prevents autoimmune encephalomyelitis

In multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) the cytokines tumour necrosis factor-alpha (TNF), lymphotoxin-alpha (LT), and interferon-gamma (IFN-gamma) are of central pathogenetic importance. A therapy capable of stopping neurological deterioration in MS patients is not yet available. Here, we report that rolipram, a selective type IV phosphodiesterase inhibitor, stereospecifically suppresses the production of TNF/LT and less strongly also IFN-gamma in human and rat auto-reactive T cells. Moreover, we show that rolipram is an effective treatment for EAE. Rolipram has extensively been studied in humans for the treatment of depression, but has not yet been marketed. The data presented here identify rolipram as potential therapy for multiple sclerosis and provoke the immediate initiation of clinical trials.

Complementary DNA for human glioblastoma-derived T cell suppressor factor, a novel member of the transforming growth factor-beta gene family

Human glioblastoma cells secrete a peptide, termed glioblastoma-derived T cell suppressor factor (G-TsF), which has suppressive effects on interleukin-2-dependent T cell growth. As shown here, complementary DNA for G-TsF reveals that G-TsF shares 71% amino acid homology with transforming growth factor-beta (TGF-beta). In analogy to TGF-beta it is apparently synthesized as the carboxy-terminal end of a precursor polypeptide which undergoes proteolytic cleavage to yield the 112 amino-acid-long mature form of G-TsF. Comparison of the amino-terminal sequence of G-TsF with that of porcine TGF-beta 2 and bovine cartilage-inducing factor B shows complete homology, which indicates that we have cloned the human analogue of these factors. It is tempting to consider a role for G-TsF in tumor growth where it may enhance tumor cell proliferation in an autocrine way and/or reduce immunosurveillance of tumor development.

T cell suppressor factor from human glioblastoma cells is a 12.5-kd protein closely related to transforming growth factor-beta

T cell suppressor factor produced by human glioblastoma cells inhibits T cell proliferation in vitro and more specifically interferes with interleukin-2 (IL-2)-dependent T cell growth. Here we report the purification of this factor from conditioned medium of the human glioblastoma cell line 308. Amino-terminal sequence analysis of the 12.5-kd protein demonstrates that eight out of the first 20 amino acids are identical to human transforming growth factor-beta. Purified glioblastoma-derived T cell suppressor factor and transforming growth factor-beta from porcine platelets inhibit both IL-2-induced proliferation of ovalbumin-specific T helper cells and lectin-induced thymocyte proliferation with similar specific activities. If released by glioblastoma cells in vivo, the factor may contribute to impaired immunosurveillance and to the cellular immunodeficiency state detected in the patients.

Probing the partly folded states of proteins by limited proteolysis

The folding of a polypeptide chain of a relatively large globular protein into its unique three-dimensional and functionally active structure occurs via folding intermediates. These partly folded states of proteins are difficult to characterize, because they are usually short lived or exist as a distribution of possible conformers. A variety of experimental techniques and approaches have been utilized in recent years in numerous laboratories for characterizing folding intermediates that occur at equilibrium, including spectroscopic techniques, solution X-ray scattering, calorimetry and gel filtration chromatography, as well as genetic methods and theoretical calculations. In this review, we focus on the use of proteolytic enzymes as probes of the structure and dynamics of folding intermediates and we show that this simple biochemical technique can provide useful information, complementing that obtained by other commonly used techniques and approaches. The key result of the proteolysis experiments is that partly folded states (molten globules) of proteins can be sufficiently rigid to prevent extensive proteolysis and appear to maintain significant native-like structure.

Interleukin 1 activity in the synovial fluid of patients with rheumatoid arthritis

The synovial fluids (SF) of patients with rheumatoid arthritis (RA) were investigated for their effects on thymocytes of C3H/HeJ mice. Of the 20 SF tested, 17 (85%) showed an augmentation of the phytohaemagglutinin (PHA) induced thymocyte stimulation. Out of 16 SF of patients with osteoarthrosis, such an activity was detected in only one (6.25%). Further characterisation of the amplification factor revealed that (1) the SF of RA patients augmented both the PHA and the Concanavalin A response of the thymocytes (2) in the absence of mitogens, SF-treated thymocytes showed an increased uptake of 3H-thymidine, (3) the SF did not propagate the growth of an interleukin 2 dependent ovalbumin specific T cell clone, but (4) the SF were found to be required for optimal interleukin 2 release by spleen cells stimulated with suboptimal doses of lectin. Based on these biological effects the factor in the SF of RA patients is suggested to represent an interleukin 1 (IL-1). IL-1 produced in cultures by activated macrophages has been shown to stimulate T and B cell functions and to induce the production of collagenase and prostaglandins by cultured synovial cells. Both properties of IL-1 could be relevant in the pathogenesis of RA.

Global epidemiology of Duchenne muscular dystrophy: an updated systematic review and meta-analysis

Background

Duchenne Muscular Dystrophy (DMD) is a rare disorder caused by mutations in the dystrophin gene. A recent systematic review and meta-analysis of global DMD epidemiology is not available. This study aimed to estimate the global overall and birth prevalence of DMD through an updated systematic review of the literature.

Methods

MEDLINE and EMBASE databases were searched for original research articles on the epidemiology of DMD from inception until 1st October 2019. Studies were included if they were original observational research articles written in English, reporting DMD prevalence and/or incidence along with the number of individuals of the underlying population. The quality of the studies was assessed using a STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) checklist adapted for observational studies on rare diseases. To derive the pooled epidemiological prevalence estimates, a meta-analysis was performed using random-effects logistic models for overall and birth prevalence and within two different underlying populations (i.e. all individuals and in males only), separately. Heterogeneity was assessed using Cochran’s Q-test along with its derived measure of inconsistency I².

Results

A total of 44 studies reporting the global epidemiology of DMD were included in the systematic review and only 40 were included in the meta-analysis. The pooled global DMD prevalence was 7.1 cases (95% CI: 5.0–10.1) per 100,000 males and 2.8 cases (95% CI: 1.6–4.6) per 100,000 in the general population, while the pooled global DMD birth prevalence was 19.8 (95% CI:16.6–23.6) per 100,000 live male births. A very high between-study heterogeneity was found for each epidemiological outcome and for all underlying populations (I² > 90%). The test for funnel plot asymmetry suggested the absence of publication bias. Of the 44 studies included in this systematic review, 36 (81.8%) were assessed as being of medium and 8 (18.2%) of low quality, while no study was assessed as being of high quality.

Conclusions

Generating epidemiological evidence on DMD is fundamental to support public health decision-making. The high heterogeneity and the lack of high quality studies highlights the need to conduct better quality studies on rare diseases.

Production of B cell stimulatory factor-2 and interferon gamma in the central nervous system during viral meningitis and encephalitis. Evaluation in a murine model infection and in patients

Synthesis of B cell-stimulating factor-2 (BSF-2) and IFN-gamma was shown in cerebrospinal fluids (CSF) collected from mice with experimental viral meningitis. In the CSF, the level of BSF-2 started to increase 24 h after intracerebral infection with lymphocytic choriomeningitis virus (LCMV) with rapid increase after day 4. IFN-gamma was not detected in the CSF before day 5 or 6 after infection, but increased sharply thereafter. In athymic nude mice, LCMV infection did not result in meningitis, and both BSF-2 and IFN-gamma levels were only slightly and transiently elevated. These findings suggest that activated mature T cells are required for development of disease and production of both BSF-2 and IFN-gamma. As observed in mice, BSF-2 was also detected in 16 out of 19 CSF samples collected from patients with acute viral infections of the central nervous system (CNS). Intrathecal production of BSF-2 and IFN-gamma may be instrumental in local production of antiviral antibodies by B lymphocytes/plasma cells invading the CNS during viral CNS disease.

Protooncogene bcl-2 gene transfer abrogates Fas/APO-1 antibody-mediated apoptosis of human malignant glioma cells and confers resistance to chemotherapeutic drugs and therapeutic irradiation

The majority of human malignant glioma cells express Fas/APO-1 and are susceptible to Fas/APO-1 antibody-mediated apoptosis in vitro. The sensitivity of Fas/APO-1-positive glioma cell lines to Fas/APO-1 antibody-mediated killing correlates inversely with the constitutive expression of the antiapoptotic protooncogene bcl-2. Here we report that BCL-2 protein expression of human glial tumors in vivo correlates with malignant transformation in that BCL-2 immunoreactive glioma cells were more abundant in WHO grade III/IV gliomas than in grade I/II gliomas. Fas/APO-1 antibody-sensitive human glioma cell lines stably transfected with a murine bcl-2 cDNA acquired resistance to Fas/APO-1 antibody-mediated apoptosis. Forced expression of bcl-2 also attenuated TNF alpha-mediated cytotoxicity of glioma cell lines in the presence of actinomycin D and cycloheximide and conferred partial protection from irradiation and the cancer chemotherapy drugs, cisplatin and BCNU. Preexposure of the glioma cell lines to the cytokines, IFN gamma and TNF alpha, which sensitize for Fas/APO-1-dependent killing, partially overcame bcl-2-mediated rescue from apoptosis, suggesting that multimodality immunotherapy involving cytokines and Fas/APO-1 targeting might eventually provide a promising approach to the treatment of human malignant gliomas.

Tumor necrosis factor alpha in cerebrospinal fluid during bacterial, but not viral, meningitis. Evaluation in murine model infections and in patients

To evaluate the potential role of cachectin/TNF-alpha in the pathogenesis of bacterial and viral meningitis, concentrations and kinetics of TNF-alpha were determined in cerebrospinal fluid (CSF). After intracerebral, but not systemic, infection with Listeria monocytogenes in mice, TNF-alpha was detected as early as 3 h after infection reaching maximum titers after 24 h. However, TNF-alpha was not found in serum during the course of Listeria infection. In contrast to bacterial meningitis, no TNF-alpha was detected at any time in CSF of mice suffering from severe lymphocytic choriomeningitis induced by intracerebral infection with lymphocytic choriomeningitis virus. This difference is striking since both model infections led to a massive infiltration of polymorphonuclear and mononuclear leukocytes into the meninges and CSF. The results found for the two model infections were paralleled by findings in humans; CSF from three out of three patients with bacterial meningitis examined during the first day of hospitalization showed significant levels of TNF-alpha; none of the CSF obtained later than 3 d after hospitalization was positive. In addition, similarly to what was found in mice with viral meningitis, zero out of seven patients with viral meningitis had detectable TNF-alpha in CSF.

Human immunodeficiency virus type 1 (HIV-1) infection of the central nervous system: an evaluation of cytokines in cerebrospinal fluid

Cytokines play an important role not only for initiation of immune reactivity but also for development of tissue injury. Of 38 patients infected with human immunodeficiency virus type 1 (HIV-1) interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) were identified in cerebrospinal fluid (CSF) of 22 (58%) and 16 (42%) patients, respectively. Among the IL-1 beta- and IL-6-positive CSF were eight of 15 HIV-1 patients with no clinical signs of central nervous system involvement and four of five patients with acquired immunodeficiency syndrome (AIDS) dementia complex. The presence of IL-6 was often associated with IL-1 beta and soluble interleukin-2 receptor in CSF as well as with intrathecal IgG synthesis. In none of the CSF samples tumor necrosis factor-alpha or interleukin-2 was detected.