The proinflammatory mediator macrophage migration inhibitory factor induces glucose catabolism in muscle

Severe infection or tissue invasion can provoke a catabolic response, leading to severe metabolic derangement, cachexia, and even death. Macrophage migration inhibitory factor (MIF) is an important regulator of the host response to infection. Released by various immune cells and by the anterior pituitary gland, MIF plays a critical role in the systemic inflammatory response by counterregulating the inhibitory effect of glucocorticoids on immune-cell activation and proinflammatory cytokine production. We describe herein an unexpected role for MIF in the regulation of glycolysis. The addition of MIF to differentiated L6 rat myotubes increased synthesis of fructose 2,6-bisphosphate (F2,6BP), a positive allosteric regulator of glycolysis. Increased expression of the enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2) enhanced F2,6BP production and, consequently, cellular lactate production. The catabolic effect of TNF-alpha on myotubes was mediated by MIF, which served as an autocrine stimulus for F2, 6BP production. TNF-alpha administered to mice decreased serum glucose levels and increased muscle F2,6BP levels; pretreatment with a neutralizing anti-MIF mAb completely inhibited these effects. Anti-MIF also prevented hypoglycemia and increased muscle F2,6BP levels in TNF-alpha-knockout mice that were administered LPS, supporting the intrinsic contribution of MIF to these inflammation-induced metabolic changes. Taken together with the recent finding that MIF is a positive, autocrine stimulator of insulin release, these data suggest an important role for MIF in the control of host glucose disposal and carbohydrate metabolism.

Enhancement of oxidised low-density lipoprotein uptake by macrophages in response to macrophage migration inhibitory factor

We examined the expression of macrophage migration inhibitory factor (MIF) mRNA in murine macrophage cell line (RAW 264.7 cells) in response to oxidized low-density lipoprotein (oxLDL), and investigated the influence of MIF on the uptake and degradation of oxLDL by RAW 264.7 cells. MIF mRNA expression was markedly upregulated in the presence of oxLDL. Consistent with this, the MIF level of the culture medium was increased by stimulation with oxLDL in dose- and time-dependent manners. Next, we added recombinant rat MIF to the culture medium and examined its effects on the uptake of(125)I-labelled oxLDL. Pretreatment with MIF enhanced both the uptake and degradation of(125)I-oxLDL. Taken together, these results suggest that MIF released from macrophages in response to oxLDL stimulates oxLDL uptake and degradation in an autocrine and paracrine fashion, which potentially results in atherosclerosis.

beta(2)-glycoprotein I deficiency: prevalence, genetic background and effects on plasma lipoprotein metabolism and hemostasis

beta(2)-glycoprotein I (beta(2)-GPI=apolipoprotein H) is an important autoantigen in patients with the antiphospholipid syndrome. It also plays a role in lipoprotein metabolism, such as anti-atherogenic property, triglyceride removal, and enhancement of lipoprotein lipase. Serum beta(2)-GPI concentration of 812 apparently healthy Japanese individuals was measured by sandwich EIA. Two families with complete beta(2)-GPI deficiency were identified. In one family, all affected had increased serum LDL-cholesterol levels or smaller particle sizes of LDL, while the other had no apparent abnormality in lipid metabolism. Individuals investigated had no history of thrombosis or overt abnormalities in hemostatic tests. A thymine corresponding to position 379 of the beta(2)-GPI cDNA was deleted in every beta(2)-GPI deficient individual. The incidence of this heterozygous deficiency determined by RFLP was 6. 3% in Japanese and none in Caucasians. Heterozygotes had significantly lower concentrations of serum beta(2)-GPI than did those without the mutation, yet no significantly different lipid profiles, such as total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, apoA-I, apoB and Lp(a), were observed. A low concentration of beta(2)-GPI seemed not to be associated with apparent abnormality in lipoprotein metabolism.

Effects of beta2-glycoprotein I and monoclonal anticardiolipin antibodies on extrinsic fibrinolysis

Antiphospholipid antibodies (aPLs) are associated with an increased incidence of thrombosis, but the mechanisms responsible for thrombosis are unclear. The present study investigated the effect of both beta2-glycoprotein I (beta2-GPI) and aPLs on the activity of extrinsic fibrinolysis. The remaining tissue-plasminogen activator (t-PA) of the sample consisting of beta2-GPI, two-chain recombinant t-PA, plasminogen activator inhibitor (PAI) -1 was measured by a chromogenic assay using synthetic substrate S-2251, Glu-plasminogen, and soluble fibrin monomer. Without PAI-1, beta2-GPI did not affect t-PA activity. When 14.3 ng/ml PAI-1 was added to 3.6 U/ml t-PA, the remaining t-PA activity was increased from 48.9% to 60.4% by the addition of beta2-GPI (190 microg/ml). The effect of beta2-GPI did not require phospholipids. The beta2-GPI seems to protect t-PA activity from the inhibition by PAI-1. When monoclonal anticardiolipin antibodies (aCLs), EY1C8, and EY2C9, which were established from a patient with antiphospholipid syndrome, were further added to the mixture with a diluted phospholipid (Platelin) to investigate the influence of aPL, the remaining t-PA activity decreased to 50.1 and 80.7%. Monoclonal aCLs appeared to inhibit the effect of beta2-GPI, that is, these monoclonals inhibited the fibrinolytic activity by an elevation in PAI-1 activity. These results suggest the possibility that the impairment of fibrinolytic activity by aCLs is one of reasons for the increased incidence in thrombosis in patients with aCLs.

Radical modulating activity and cytotoxic activity of synthesized eugenol-related compounds

The ability of nine synthetic eugenol-related compounds to scavenge O2- (generated by the hypoxanthine-xanthine oxidase reaction) was compared with their radical generation and cytotoxic activity. ESR spectroscopy showed that eugenol (4-allyl-2-methoxyphenol), 2-allyl-4-methoxyphenol, 2-allyl-4-t-butylphenol and 2,4-dimethoxyphenol efficiently scavenged O2- and produced radicals under alkaline conditions. 2-allyl-4-t-butylphenol showed the highest cytotoxic activity and DNA-synthesis inhibitory activity, possibly due to the hydrophobic radical reactivity. 2-allyl-4-methoxyphenol and 2,4-dimethoxyphenol showed higher antioxidant activity than 3-t-butyl-4-hydroxyanisol (BHA), but all these compounds showed comparable cytotoxic activity with each other. These findings suggest a possible link between the cytotoxic activity and radical generation/scavenging activity in eugenol-related compounds.

Association of autoantibodies against the phosphatidylserine-prothrombin complex with manifestations of the antiphospholipid syndrome and with the presence of lupus anticoagulant

OBJECTIVE

To clarify the association of autoantibodies against prothrombin with the clinical manifestations of the antiphospholipid syndrome (APS) and with the presence of lupus anticoagulant (LAC).

METHODS

We examined 265 patients who visited our autoimmune disease clinic. IgG and IgM antiprothrombin antibodies were tested by enzyme-linked immunosorbent assay (ELISA) as either antiphosphatidylserine-prothrombin complex (aPS/PT) antibodies or as antibodies against prothrombin coated on irradiated ELISA plates (as antigen) (aPT). IgG, IgM, and IgA anticardiolipin (aCL) antibodies and their beta2-glycoprotein I (beta2GPI) dependency were also evaluated by ELISA. LAC was tested by 3 different methods.

RESULTS

The presence of aPS/PT, but not of aPT, significantly correlated with the clinical manifestations of APS (odds ratio [OR] 4.39, 95% confidence interval [95% CI] 2.06-9.38), and aPS/PT antibodies were as specific as beta2GPI-dependent aCL for APS (93.1% for both). IgG aPS/PT strongly correlated with the presence of LAC as detected using the dilute Russell viper venom time test (OR 38.2, 95% CI 13.4-109.1).

CONCLUSION

Antiprothrombin antibodies are heterogeneous and their clinical relevance depends on the method of detection applied. Positive results on the aPS/PT test can serve as a marker of thrombotic events in patients with autoimmune diseases.

Coagulation and fibrinolytic activities in 2 siblings with beta(2)-glycoprotein I deficiency

beta(2)-Glycoprotein I (beta(2)GPI) is a major antigen for antiphospholipid antibodies, and its multiple in vitro functions have been reported. This glycoprotein not only down-regulates thrombin formation by inhibiting contact activation or prothrombinase activity, but also up-regulates coagulation by reducing protein C anticoagulant activity. However, the in vivo roles of beta(2)GPI remain obscure. Coagulation and fibrinolytic characteristics were investigated in individuals with beta(2)GPI deficiency. An apparently healthy woman and her brother are homozygotes for beta(2)GPI deficiency. In these patients, Russell viper venom time was shortened (40.4 seconds; normal range, 47.8 +/- 4.95 seconds), but all markers of thrombin generation and fibrin turnover were within normal ranges. Exogenous activated protein C adequately prolonged the clotting time of the beta(2)GPI-deficient plasma, and euglobulin lysis time was also normal. Thus, elevated thrombin generation, enhancement of activated protein C response, and an altered fibrinolytic system were not found in congenitally beta(2)GPI-deficient plasma. (Blood. 2000;96:1594-1595)

Proteolytic cleavage of beta(2)-glycoprotein I: reduction of antigenicity and the structural relationship

Binding of beta(2)-glycoprotein I (beta(2)-GPI)-dependent anticardiolipin antibodies (aCL) derived from antiphospholipid syndrome (APS) is significantly reduced in aCL ELISA due to loss of the phospholipid (PL) binding property of beta(2)-GPI by plasmin treatment. In the present study, the treatment generated a nicked form of beta(2)-GPI and resulted in loss of antigenicity for the autoantibodies detected in ELISA, using an beta(2)-GPI directly adsorbed polyoxygenated carboxylated plate, the assay system of which was not related to PL binding. The nicked form bound to neither Cu(2+)-oxidized low-density lipoprotein (oxLDL) nor to beta(2)-GPI-specific lipid ligands isolated from oxLDL, the result being a complete loss of subsequent binding of anti-beta(2)-GPI autoantibodies. The conformational change in the nicked domain V was predicted from its intact structure determined by an X-ray analysis (implemented in Protein Data Bank: 1C1Z), molecular modeling and epitope mapping of a monoclonal anti-beta(2)-GPI antibody, i.e. Cof-18, which recognizes the related structure. The analysis revealed that novel hydrophobic and electrostatic interactions appeared in domain V after the cleavage, thereby affecting the PL binding of beta(2)-GPI. Such a conformational change may have important implications for exposure of cryptic epitopes located in the domains such as domain IV.

Cytotoxicity of methyl methacrylate (MMA) and related compounds and their interaction with dipalmitoylphosphatidylcholine (DPPC) liposomes as a model for biomembranes

OBJECTIVE

To clarify the potential mechanism of action of methyl methacrylate (MMA) and related compounds to membranes of living cells, compared with their interaction with dipalmitoylphosphatidylcholine (DPPC) liposomes as a model for biological membranes.

MATERIALS AND METHODS

For (meth)acrylates, MMA, ethyl acrylate(EA), n-butyl acrylate (BA) and n-butyl methacrylate (BMA) and for living cells, primary human gingival fibroblast (HGF), human submandibular gland adenocarcinoma cell line (HSG) and human erythrocytes were used. The physicochemical changes in DPPC liposomes induced by (meth)acrylates were studied using differential scanning calorimetry (DSC) and nuclear magnetic resonance spectroscopy (NMR).

RESULTS

Cytotoxicity decreased as follows: BA > BMA > EA > MMA. Changes in phase transition properties (temperature Tm, enthalpy delta H and Height/Half-Height Width (H/HHW) of DSC peak were decreased as follows: BA > EA > MMA. BMA enhanced H/HHW and increased Tm slightly. NMR-shielding effect decreased as follows: BMA > MMA > BA, EA.

CONCLUSION

BA and BMA exhibited large cytotoxicity and high DPPC-interaction due to their lipophilicity, compared to EA or MMA. MMA showed little cytotoxicity and small changes in DPPC liposomes, whereas BA showed large cytotoxicity and large changes in the liposomes characterized by the membrane disturbance. Haemolytic activity and cytotoxicity of acrylates were higher than those of methacrylates. The physico-chemical properties (Log P or Q sigma) of (meth)acrylates affect the lipid bilayer in biological membranes.

Cytotoxic activity of low molecular weight polyphenols against human oral tumor cell lines

A total of 150 chemically-defined natural and synthetic polyphenols (flavonoids, dibenzoylmethanes, dihydrostilbenes, dihydrophenanthrenes and 3-phenylchromen-4-ones), with molecular weights ranging from 224 to 824, were investigated for cytotoxic activity against normal, tumor and human immunodeficiency virus (HIV)-infected cells. They showed higher cytotoxic activity against human oral squamous cell carcinoma HSC-2 and salivary gland tumor HSG cell lines than against normal human gingival fibroblasts HGF. Many of the active compounds had a hydrophilic group (hydroxyl group) in the vicinity of a hydrophobic group (prenyl, phenyl, methylcyclohexene or methylbenzene moiety), similar to isoprenoid-substituted flavones. Substitution of hydrophobic group (prenyl or geranyl group) did not significantly change the cytotoxic activity of flavanones, isoflavans, chalcones or 5-hydroxy-3-phenoxychromen-4-ones. However, the prenylation(s) of an isoflavone and a 2-arylbenzofuran significantly enhanced the cytotoxic activity. Agarose gel electrophoresis showed that active components induced internucleosomal DNA fragmentation in human promyelocytic leukemic HL-60 cells, but not in HSC-2 cells. Most of the polyphenols failed to reduce the cytophathic effect of HIV infection in MT-4 cells.

Cytotoxicity and radical intensity of eugenol, isoeugenol or related dimers

To investigate the possible link between radicals and cytotoxicity of eugenol-related compounds, dimer compounds were synthesized from eugenol (4-allyl-2-methoxyphenol) or isoeugenol (4-propenyl-2-methoxyphenol): bis-eugenol (3,3'-dimethoxy-5,5'-di-2-propenyl-1,1'-biphenyl-2,2'-diol); dehydrodiisoeugenol (2-(3-methoxy-4-hydroxyphenyl)-3-methyl-5-(1-propenyl)-7-methoxy-2,3- dihydrobenzofuran) and alpha-di-isoeugenol (r-l-ethyl-5-hydroxy-t-3-(4-hydroxy-3-methoxyphenyl)-6-methoxy-c-2- methylindane). Both the cytotoxic activity and the DNA synthesis inhibitory activity of these compounds against a salivary gland tumor cell line (HSG) and normal human gingival fibroblast (HGF) were decreased in the order of: dehydrodiisoeugenol, alpha-di-isoeugenol > isoeugenol > eugenol > bis-eugenol. Electron spin resonance (ESR) spectroscopy showed that dehydrodiisoeugenol, alpha-di-isoeugenol and eugenol, but not isoeugenol and bis-eugenol, produced phenoxyl radicals under alkaline condition (pH > 9.5). However, benzyl radicals were produced during the dimerization of isoeugenol to dehydrodiisoeugenol. The radical intensity of alpha-di- and dehydrodiisoeugenol appeared at relatively later incubation time than eugenol, suggesting that their phenoxyl radical was more stable than that of eugenol. Such a phenoxyl radical is produced by scavenging free radicals, during the inhibition of lipid peroxidation. Higher cytotoxic activity of isoeugenol dimers was thought to be induced by interaction with cell membranes via the lipophilic radical. The present study supports the notion that relative cytotoxicity of chemicals can be evaluated by measuring the radical intensity using ESR.

Antiphospholipid antibodies in leprotic patients: a correlation with disease manifestations

OBJECTIVES

Previous studies showed that antiphospholipid antibodies (aPL) are frequent in the sera of leprosy patients and are most probably directed against body tissue cardiolipins. Some groups have demonstrated differences between the binding specificity of "autoimmune-aPL" and "non-autoimmune-aPL". It is widely accepted that a plasma protein, beta 2-Glycoprotein I (beta 2-GPI), is required for the binding of autoimmune anticardiolipin antibodies (aCL) to cardiolipin. However, some reports suggested heterogeneity of leprosy aCL with respect to their beta 2-Glycoprotein I (beta 2GPI) dependency, although no thromboembolic complications have been reported. This study was designed to assess the specificity of aPL by investigating the prevalence of aCL, anti-phosphatidylserine (aPS), anti-phosphatidylinositol (aPI), anti-beta 2GPI and antiprothrombin (aPT) antibodies, and evaluate their clinical significance in a group of patients with lepromatous leprosy.

PATIENTS AND METHODS

35 lepromatous leprosy patients were selected randomly from an Egyptian leprosarium as a study group. 35 normal household contact controls were selected matching the study group for both sex and age. aCL, aPS, aPI, aPT, anti-beta 2GPI and beta 2-dependent aCL antibodies were investigated by ELISA in all patients and controls.

RESULTS

aCL antibodies were more frequent in leprosy patients than in controls [13/35 (37%) vs. 3/35 (9%), respectively, p = 0.02] and significantly correlated with Raynaud's phenomenon, skin nodules, chronic skin ulcers and urticarial skin rash. No association was found with hypopigmentation, hyperpigmentation and saddle nose. None of the patients presented aPS nor aPI. Only 1 subject from the control group presented aPI along with aCL. aPT were present in 2/35 (5.7%) and anti-beta 2GPI in 1/35 (2.9%) leprotic patients. None of the individuals from the control group presented aPT nor anti-beta 2GPI.

CONCLUSIONS

An association was found between the presence of aCL and certain dermatological manifestations of leprosy, such as Raynaud's phenomenon, skin nodules, chronic skin ulcers and urticarial skin rash. As in other infectious diseases, there was a lack of beta 2GPI-dependency and an absence of thrombotic complications.

[Avascular necrosis of the femoral head caused by steroid treatment in neurosurgery]

Steroid induced avascular necrosis of the femoral head is a well known disease, but, there are few reports about the disease in neurosurgical patients. In the neurosurgical field, the use of steroids has become prevalent since the 1960's. Recently, the adverse effect of steroids and the limitation of its effect have been highlighted, but its use against neurosurgical diseases is still a common treatment to prevent cerebral edema or to counteract hypo-pituitarism caused by hypophyseal lesions. We reviewed 250 patients of avascular necrosis treated between 1985 and 1997 in our institute. Within these patients, 11 (4.4%) were treated with steroid during neurosurgical treatment. Six patients were treated for brain tumors near hypophyseal lesions, and 5 patients were treated for head injury or cerebro-vascular disease. It is concluded that total steroid dose over 5000 mg such as hydrocortisone may become a high risk for causing avascular necrosis of the femoral had in neurosurgical disease, and it may occur even with the supplemental steroid treatment against hypo-pituitarism. The onset is usually 2 or 3 years after the neurosurgical treatment, when neurosurgical care is no longer needed. Therefore, it tends to be ignored in the neurosurgical field. The treatments against avascular necrosis of the femoral head were femoral head osteotomy or conservative management, and good results were obtained. Early diagnosis and early treatment is essential. Further consideration concerning steroid treatment in neurosurgical patients may be required.

[Evaluation of F1 + 2/TAT ratios in Japanese patients with antiphospholipid syndrome]

The clinical manifestations of the antiphospholipid syndrome(APS) include arterial and venous thrombosis and a fetal loss, but the pathogenic mechanisms remain unclear. To clarify the mechanism of thrombogenic state in APS, we investigated the markers for thrombosis including thrombin-antithrombin complex(TAT) in patients with antiphospholipid antibodies(aPL). Prothrombin fragment 1 + 2(F1 + 2) in patients with APS and in autoimmune disease patients with aPL increased significantly compared with those obtained in autoimmune disease patients without aPL or in control subjects. However, there was not a significant difference in the TAT level of each group, suggesting that the formation of TAT was impeded in APS. To investigate which aPL is responsible for the disturbance of the TAT formation, the ratio of F1 + 2/TAT was calculated. The ratio increased in patients with lupus anticoagulant, especially with prolonged kaolin clotting time, and furthermore the ratio strongly increased in patients with IgG type-anticardiolipin antibodies(aCL). Our results suggest that IgG-aCL is associated with thrombogenic state in APS because free thrombin is present in patients' blood by impeding the formation of TAT by mainly IgG-aCL.

The blood supply of the lateral epiphyseal arteries in Perthes' disease

We performed superselective angiography in 28 hips in 25 patients with Perthes' disease in order to study the blood supply of the lateral epiphyseal arteries (LEAs). Interruption of the LEAs at their origin was observed in 19 hips (68%). Revascularisation in the form of numerous small arteries was seen in ten out of 11 hips in the initial stage of Perthes' disease, in seven of eight in the fragmentation stage and in five of nine in the healing stage. Penetration of mature arteries into the depths of the epiphysis was seen in four of nine hips in the healing stage. Vascular penetration was absent in the weight-bearing portion of the femoral head below the acetabular roof. Interruption of the posterior column artery was seen where it passed through the capsule in seven hips when they lay either in internal rotation or in abduction with internal rotation. We suggest that in Perthes' disease the blood supply of the LEAs is impaired at their origin and that revascularisation occurs from this site by ingrowth of small vessels into the femoral epiphysis. This process may be the result of recurrent ischaemic episodes.

The blood supply of the lateral epiphyseal arteries in Perthes’ disease

We performed superselective angiography in 28 hips in 25 patients with Perthes’ disease in order to study the blood supply of the lateral epiphyseal arteries (LEAs). Interruption of the LEAs at their origin was observed in 19 hips (68%). Revascularisation in the form of numerous small arteries was seen in ten out of 11 hips in the initial stage of Perthes’ disease, in seven of eight in the fragmentation stage and in five of nine in the healing stage. Penetration of mature arteries into the depths of the epiphysis was seen in four of nine hips in the healing stage. Vascular penetration was absent in the weight-bearing portion of the femoral head below the acetabular roof. Interruption of the posterior column artery was seen where it passed through the capsule in seven hips when they lay either in internal rotation or in abduction with internal rotation.

We suggest that in Perthes’ disease the blood supply of the LEAs is impaired at their origin and that revascularisation occurs from this site by ingrowth of small vessels into the femoral epiphysis. This process may be the result of recurrent ischaemic episodes.

Cytotoxic activity of hydrolyzable tannins against human oral tumor cell lines--a possible mechanism

Hydrolyzable tannins showed higher cytotoxic activity against human oral squamous cell carcinoma and salivary gland tumor cell lines than against normal human gingival fibroblasts, whereas gallic acid, a component unit of tannins, showed much weaker selective cytotoxicity. The cytotoxic activity of dimeric compounds was generally higher than that of monomeric compounds. Macrocyclic ellagitannin oligomers, such as oenothein B, woodfordin C and woodfordin D showed the greatest cytotoxic activity, and their activity (per given number of molecules) was one order higher than those of gallic acid and epigallocatechin gallate, a major component of green tea. These compounds induced apoptotic cell death characterized by DNA fragmentation (as demonstrated by the TUNEL method) and cleavage of cytokeratin 18 by activated caspase(s) (as demonstrated by M30 monoclonal antibody). ESR spectroscopy revealed that these macrocyclic compounds at higher concentrations produced their own radicals and significantly enhanced the radical intensity of sodium ascorbate, possibly by their prooxidant actions. Catalase failed to eliminate their apoptosis-inducing activity, reducing the possibility of the involvement of hydrogen peroxide production in the extracellular fraction. These observations suggested that the antitumor activity of macrocyclic ellagitannin oligomers reported previously might be explained by their apoptosis-inducing activity.

Association of antiphosphatidylserine/prothrombin autoantibodies with HLA class II genes

OBJECTIVE

To investigate the associations between HLA class II genes and antiphosphatidylserine/prothrombin antibodies (aPS/PT) in a group of British caucasoid patients with antiphospholipid antibodies (aPL).

METHODS

This study included 82 patients with aPL. IgG aPS/PT were detected in sera using enzyme-linked immunosorbent assays. HLA-DQB1, DQA1, and DRB1 genotypes were determined by polymerase chain reaction using sequence-specific primers. All results were compared with 177 matched healthy control subjects.

RESULTS

IgG aPS/PT were present in 41 of 82 patients (50%). The frequencies of DQB1*0301/4, DQB1*0604/5/6/7/9, and DRB1*1302 alleles were increased in patients with aPS/PT compared with controls. To minimize the interference of the association between anti-beta2-glycoprotein I (anti-beta2GPI) and HLA, patients with anti-beta2GPI were excluded from further analyses, and only HLA-DQB1*0301/4 remained significant compared with controls (odds ratio [OR] 2.75, 95% confidence interval [95% CI] 1.2-6.5, P < 0.03). In the haplotype analysis, HLA-DQB1*0301/4;DQA1* 0301/2;DRB1*04 was significantly increased in patients with IgG aPS/PT compared with controls (OR 4.75, 95% CI 1.72-13.10, P = 0.0063).

CONCLUSION

The HLA-DQB1*0301/4;DQA1*0301/ 2;DRB1*04 haplotype and its components may influence the production of aPS/PT in the antiphospholipid syndrome, which partly explains the correlation between the lupus anticoagulant and DQB1*03.

Dissection of signaling cascades through gp130 in vivo: reciprocal roles for STAT3- and SHP2-mediated signals in immune responses

We generated a series of knockin mouse lines, in which the cytokine receptor gp130-dependent STAT3 and/or SHP2 signals were disrupted, by replacing the mouse gp130 gene with human gp130 mutant cDNAs. The SHP2 signal-deficient mice (gp130F759/F759 were born normal but displayed splenomegaly and lymphadenopathy and an enhanced acute phase reaction. In contrast, the STAT3 signal-deficient mice (gp130FXQ/FXXQ) died perinatally, like the gp130-deficient mice (gp130D/D). The gp130F759/F759 mice showed prolonged gp130-induced STAT3 activation, indicating a negative regulatory role for SHP2. Th1-type cytokine production and IgG2a and IgG2b production were increased in the gp130F759/F759 mice, while they were decreased in the gp130FXXQ/FXXQ immune system. These results indicate that the balance of positive and negative signals generated through gp130 regulates the immune responses.