Epitope specificity of monoclonal anti-beta 2-glycoprotein I antibodies derived from patients with the antiphospholipid syndrome

beta 2-Glycoprotein I (beta 2GPI) has been identified as a cofactor in the recognition of the phospholipid Ag cardiolipin (CL) by anticardiolipin Ab (aCL) purified from patients with autoimmune diseases. However, there is considerable controversy as to the exact nature of the epitopes to which these Abs are directed. mAb derived from patients with the antiphospholipid syndrome bound to CL only in the presence of beta 2GPI. Synthetic peptides that span the fifth C-terminal domain of beta 2GPI supported the binding of one of the mAbs to CL in a beta 2GPI-free system. These peptides possessed the phospholipid binding sequence Cys281-Lys-Asn-Lys-Glu-Lys-Lys-Cys288. Three of the mAbs bound to beta 2GPI that had been adsorbed on gamma-irradiated microtiter plates. Binding to beta 2GPI was inhibited in a dose-dependent manner by the peptides from the carboxyl-terminal end of beta 2GPI and soluble beta 2GPI, indicating that the mAb bound to peptides and beta 2GPI in free solution. Thus, mAbs derived from patients with the antiphospholipid syndrome have specificity for epitopes on the fifth domain of beta 2GPI. Our results support the idea that beta 2GPI acts as a primary Ag for these Abs.

Pattern of cytokine production by T cells from adolescents with asthma in remission, after stimulation with Dermatophagoides farinae antigen

Children with asthma usually become asymptomatic by the time they reach age 20 y. To clarify the immunologic mechanisms responsible for this phenomenon, we studied patients in remission and others who still had frequent asthma attacks. Patients were grouped by clinical status, and three variables were measured: serum levels of IgE, production of IL4 and interferon (IFN)-gamma, and the activation of T cells induced by Dermatophagoides farinae (Df) antigen. Df-induced activation of T cells (as measured by antigen-induced IL2 responsiveness) or IL2 synthesis itself was induced in patients with active asthma but not in normal subjects. These responses were much weaker in patients in remission. When stimulated by Df antigen in vitro, lymphocytes from patients with active asthma produced much more IL4 than did the cells from normal subjects, and cells from patients in remission produced only a small amount. In contrast, under similar conditions lymphocytes from patients with active asthma produced less IFN-gamma than did the cells from normal subjects. Production of IFN-gamma stimulated by Df antigen was high in patients in remission but not in normal subjects. Thus, upregulated IFN-gamma production after exposure to Df antigen might reduce IL4 secretion, which would suppress IgE production and would improve clinical status. Df antigen may suppress Df-induced allergic responses in patients with asthma in remission.

Epitope specificity of monoclonal anti-beta 2-glycoprotein I antibodies derived from patients with the antiphospholipid syndrome

beta 2-Glycoprotein I (beta 2GPI) has been identified as a cofactor in the recognition of the phospholipid Ag cardiolipin (CL) by anticardiolipin Ab (aCL) purified from patients with autoimmune diseases. However, there is considerable controversy as to the exact nature of the epitopes to which these Abs are directed. mAb derived from patients with the antiphospholipid syndrome bound to CL only in the presence of beta 2GPI. Synthetic peptides that span the fifth C-terminal domain of beta 2GPI supported the binding of one of the mAbs to CL in a beta 2GPI-free system. These peptides possessed the phospholipid binding sequence Cys281-Lys-Asn-Lys-Glu-Lys-Lys-Cys288. Three of the mAbs bound to beta 2GPI that had been adsorbed on gamma-irradiated microtiter plates. Binding to beta 2GPI was inhibited in a dose-dependent manner by the peptides from the carboxyl-terminal end of beta 2GPI and soluble beta 2GPI, indicating that the mAb bound to peptides and beta 2GPI in free solution. Thus, mAbs derived from patients with the antiphospholipid syndrome have specificity for epitopes on the fifth domain of beta 2GPI. Our results support the idea that beta 2GPI acts as a primary Ag for these Abs.

Effect of thyrotropin-releasing hormone on serum thyroid hormones: a study in the patients with untreated and treated Graves' disease and subacute thyroiditis

In order to investigate the extrapituitary action of TRH on the thyroid, serum T3, T4, and TSH levels after im administration of TRH were analyzed in 63 patients with untreated hyperthyroid Graves' disease, in 60 euthyroid patients with treated Graves' disease, in 8 patients with subacute thyroiditis, and in 140 healthy subjects. TRH administration in the healthy subjects resulted in a significant increase in serum T3 and T4 levels after 2 h. However, in the patients with untreated hyperthyroid Graves' disease, a significant decrease in serum T3 and T4 levels with undetectable TSH was found 2 h after TRH administration. In the patients with subacute thyroiditis, serum T3 levels also significantly decreased after TRH administration. When a decrease in serum T3 and T4 levels after TRH administration in the patients with hyperthyroid Graves' disease was analyzed in terms of thyroid microsomal antibody and thyroglobulin antibody, a decrease in serum T3 and T4 levels was largest in patients with thyroid microsomal antibody and thyroglobulin antibody. In contrast, an increase in serum T3 and T4 levels in response to TRH in the euthyroid patients with Graves' disease was largest in patients without thyroid autoantibodies. It is concluded that TRH acts directly on the thyroid to suppress the thyroid hormone secreting activity in the absence of circulating TSH and that thyroid autoantibodies affect thyroidal response after TRH administration.

Generation of novel rapamycin structures by microbial manipulations

A new rapamycin producing culture was isolated and designated as Actinoplanes sp. N902-109. The addition of a cytochrome P-450 inhibitor and precursor feeding using this culture, and biotransformation approaches generated new rapamycin analogs with modifications at C-4, C-9, C-16, C-27, C-28 and/or C-39. The immunosuppressive activity of the resulting analogs was established in the mixed lymphocyte reaction assay.

[A case of melorheostosis with linear sclerodermatous skin changes]

A 69-years old Japanese woman complained of pain in the left elbow joint and thickened skin over the left upper limb. The pain had been present for 20 years, and the thickened area of the skin gradually enlarged during this period. Her left elbow joint showed some limitation of motion. There was no record of any similar condition in her family history. Radiographs of the left limb showed cortical hyperostosis extending from the middle of the left humerus to the distal end of the radius. Radiographs of the other limbs were normal. A technetium 99m-methylene diphosphonate bone scintigraphy revealed increased uptake in the areas of radiographic hyperostosis. The diagnosis of melorheostosis was made. Skin biopsy of thickened area was performed. The epidermis was normal, and proliferation of normal-appearing collagen fibers into the subcutaneous fat was noted. No inflammatory changes were found. The cause of sclerodermatous skin changes was thought to be not by linear scleroderma but by melorheostosis. In cases of linear sclerodermatous changes, melorheostosis as its origin should be considered.

[The association of the disease activity of rheumatoid factor positive vasculitis and the level of rheumatoid factor]

Rheumatoid factor (RF), an autoantibody against the Fc portion of denatured IgG, has long been recognized as an important biologic marker not only for rheumatoid arthritis but also for other auto-immune diseases. In this study, we measured the level of serum RF in four patients with RF positive systemic vasculitis using laser nephelometry. Three patients were diagnosed as polyarteritis nodosa and the other patient was diagnosed as systemic vasculitis without the finding of typical necrotizing vasculitis from biopsies. In the result, we found that the level of RF paralleled the disease activity in these cases. When active phase of the disease, the level of RF showed very high, and after the treatment combined with plasmapheresis, corticosteroid and immunosuppressive agent, the level of RF decreased in accordance with CRP, ESR and clinical features. These suggested that RF was the disease specific marker for RF positive vasculitis and beneficial informations for proper diagnosis and better treatment could be provided by measurement of the level of RF in patients with RF positive systemic vasculitis.

Antiphospholipid syndrome and the idiotypic network

To study whether monoclonal anticardiolipin antibodies (aCL), derived from patients with antiphospholipid syndrome (APS), have similar pathogenic potential, we have employed an experimental model of antiphospholipid syndrome. Monoclonal aCL were produced by the combined method of EBV transformation and somatic cell hybridization of lymphocytes, derived from patients with APS. The monoclonal aCL were used to immunize mice at the footpads and the mice were followed for serological and clinical manifestations of APS. The monoclonal antibody EY2C9, was found to bind weakly to cardiolipin and other phospholipids (i.e. phosphatidyl-serine, phosphatidyl-ethanolamine and phosphatidyl-inositol). The antibody TM1B9, although derived from a patient with SLE and with secondary APS, did not react with phospholipids. Immunization of naive BALB/c mice with EY2C9 was followed by production of sustained high titers of antiphospholipid antibodies associated with prolonged activated partial thromboplastin time (APTT) (46.8 +/- 5.0 s vs. 22.4 +/- 1.7 s, in the non-immunized mice). Mice immunized with TM1B9 had a more moderate titer of antiphospholipid antibodies and did not show prolonged APTT. The pregnant mice, that were immunized with EY2C9, had increased fetal resorption rate (the equivalent of fetal loss in the human) of 36.8 +/- 10% (vs. 2 +/- 4% in mice immunized with TM1B9). Our results confirm that monoclonal aCL, derived from a patient with APS, can have a pathogenic potential, dysregulating the idiotypic network and leading to the development of characteristic signs of APS.(ABSTRACT TRUNCATED AT 250 WORDS)

Ten-year follow-up study of thyroid function in euthyroid patients with simple goiter or Hashimoto's thyroiditis

In an attempt to study the natural course of Hashimoto's thyroiditis and simple goiter, 74 euthryroid patients with Hashimoto's thyroiditis and 212 patients with simple goiter were followed for 10 years. In 204 patients with simple goiter (96.2%) it remained as a simple goiter throughout the observation period, whereas 8 patients (3.8%) later had Hashimoto's thyroiditis as evidenced by the appearance of circulating thyroid autoantibodies. These 8 patients had HLA typing significantly different from that of control subjects. None of the patients with simple goiter had hyperthyroid Graves' disease despite the fact that 17.5% of those patients had mild to moderate exophthalmos with either Moebius' sign or von Graefe's sign. In contrast, 12 patients with Hashimoto's thyroiditis (16.2%) had exophthalmos with Moebius' sign and/or von Graefe's sign, and 4 of 12 such patients later had hyperthyroid Graves' disease. TSH binding inhibitory immunoglobulin was detected in 3 of 4 such patients with hyperthyroid Graves' disease. Forty-nine patients with Hashimoto's thyroiditis (66.2%) still remained euthyroid but 20 of those (27.0%) turned into hypothyroidism during the 10-year follow-up.

Effects of nitric oxide synthase inhibitor on hemodynamic change and O2 delivery in septic dogs

To elucidate the role of nitric oxide (NO) in septic shock, we measured hemodynamic and pulmonary gas changes in anesthetized dogs after intravenous administration of bacterial lipopolysaccharide (LPS) with or without NO synthase inhibitor, NG-nitro-L-arginine (L-NNA). Infusion of LPS (250 ng.kg-1.min-1) for 2 h decreased mean arterial pressure over 1-4 h. Although L-NNA (10 mg/kg) blocked LPS-induced hypotension, it decreased cardiac index, oxygen delivery index, arterial pH, and arterial PO2 and increased systemic vascular resistance index in the presence or absence of LPS. Administration of NG-nitro-D-arginine (D-NNA, 10 mg/kg) alone caused fewer hemodynamic effects (increased systemic vascular resistance index and decreased cardiac index) than L-NNA alone. Our study provides evidence that L-NNA prevents endotoxin-induced hypotension but decreases cardiac output and oxygen delivery, effects that may, in part, be due to a nonspecific NO synthase-independent event. Thus clinical use of NO synthase inhibitors for the treatment of septic shock should be cautiously considered.

Transcriptional regulation of human thyroid hormone receptor beta 1 gene expression: effect of human retinoid X receptor and identification of a transcriptional silencer region

Effects of human retinoid X receptor alpha (hRXR alpha) and its ligand, 9-cis-retinoic acid, on T3-mediated auto-regulation of hTR beta 1 gene expression were examined using a chloramphenicol acetyltransferase (CAT) reporter system, and a deletional analysis of the promoter. hRXR alpha enhanced T3-dependent CAT induction mediated through the proximal (p) TRE in a ligand (9-cis-retinoic acid) independent manner. In a gel mobility shift assay, hRXR alpha enhanced the binding of hTR beta 1 to the pTRE by the formation of hRXR alpha-hTR beta 1 heterodimers. On the other hand, hRXR alpha and 9-cis-retinoic acid did not show any effects on T3-dependent CAT induction mediated through the distal (d) TRE or the binding of hTR beta 1 to the dTRE. A four hundred-base pair (bp) fragment adjacent upstream of the dTRE showed a T3 independent suppressor effect on the function of the pTRE and dTRE. Thus, this region may be an important regulator of the T3 dependent up-regulation of the TR beta 1 gene expression which is observed only under specific conditions.

[Congenital color vision deficiencies as a social problem]

Color vision standards for various occupations and schools have been greatly eased recently. However, if the trend is unaccompanied with proper advice for color defective persons, there is a risk of accidents such as occurred in the past when color vision standards had not been introduced, because the color vision defect is unchanged. In this context, the history of color vision standards and the color confusion by color defective persons in their daily life were reviewed. The collected data together with pathophysiological characteristics of defective color vision suggest that at least the following measures are necessary from a practical point of view: (1) By education and awareness, color defective persons can avoid errors in color in most cases. Therefore, ophthalmologists should inform them of their defects in childhood and give instructions on how to compensate for their disadvantages. (2) In public and occupational situations, all the information conveyed by color should include lettering or other forms of redundancy for the convenience of color defective persons.

[IgE production and gene expression of interleukin-4 and interferon-gamma by peripheral mononuclear cells in asthmatic children]

In asthmatic children without he egg allergy, spontaneous IgE production of PBMC showed 1.27 +/- 0.28 IU/ml (Mean +/- SE) and IgE production of Dermatophagoides farinae (Df) stimulated PBMC after which IFN-gamma decreased to 0.89 +/- 0.23 IU/ml (Mean +/- SE) (p < 0.001). IgE production of Ovalbumin (OVA) stimulated PBMC after which IFN-gamma showed no decrease. In asthmatic children with hen egg allergy, IgE production of OVA stimulated PBMC and IFN-gamma decreased to 1.0 +/- 0.52 IU/ml (Mean +/- SE). In spontaneous IgE production it was 1.61 +/- 0.91 IU/ml. (p < 0.05). IL-4 mRNA was expressed in spontaneous PBMC in asthmatic children, but not in healthy non atopic children. The expression of IL-4 mRNA was suppressed in Df stimulated PBMC followed by IFN-gamma in asthmatic children. In asthmatic children, IFN-gamma mRNA were expressed in Df stimulated PBMC after which IFN-gamma. And simultaneously IgE production in Df stimulated PBMC were suppressed by addition of IFN-gamma.

Procoagulant properties of atherosclerotic aortas

TF protein was overexpressed by macrophages and smooth muscle cells and deposited in the extracellular matrix of atheroclerotic intimas. TF activity was also enhanced in the atherosclerotic intima, probably resulting in either thrombus formation or intimal fibrin deposition after the exposure of flowing blood and imbibed fibrinogen to TF in atherosclerotic lesions. These findings further support the hypothesis that the coagulation and fibrinolysis systems can play an essential role in the initiation and progression of atherosclerosis, and the clinical implications of this phenomenon may thus contribute to future investigations in the prevention and treatment of atherosclerotic diseases.

Expression of tissue factor and interleukin-1 beta in a novel rabbit model of disseminated intravascular coagulation induced by carrageenan and lipopolysaccharide

Thrombus formation and the sequential expression of tissue factor (TF), interleukin-1 beta (IL-1 beta) and interleukin-1 receptor antagonist (IL-1 ra) in several organs were examined immunohistochemically and morphometrically in a novel model of disseminated intravascular coagulation (DIC) developed by modifying the generalized Shwartzman reaction (GSR) in rabbits. The new model [carrageenan (CA)-lipopolysaccharide (LPS)] was induced by the administration of a priming dose of intraperitoneal CA, 10 mg/kg, followed 24 h later by a provocative dose of LPS 25 micrograms/kg, while GSR was induced by the intravenous injection of two doses of LPS 25 micrograms/kg. CA was detected predominantly within macrophages in the spleen and liver. Fibrin thrombi were formed as early as 1 h after the second LPS treatment in all examined organs reaching a peak at 3-9 h and their prevalence was higher in the CA-LPS group (p < 0.05). The sequential expressions of TF and IL-1 beta correlated well with each other in both groups reaching a peak at 3-9 h with the CA-LPS group showing a more pronounced expression than the GSR group. Macrophages in the liver, spleen and lungs, and Bowman's epithelial cells expressed both proteins, while IL-1 beta was also expressed by endothelial and epithelial cells. IL-1 ra was expressed by the same cells expressing IL-1 beta, however, its expression continued to increase gradually over 24 h. The mortality rate was lower (p < 0.05) and neutrophilic sequestration less prominent in the CA-LPS group than in the GSR group. These findings indicate that CA efficiently replaced the priming LPS treatment and the consequently enhanced production of IL-1 beta may have resulted in the upregulation of TF expression leading to the high level of thrombi in this new model which may provide a tool for further studies on the role of cytokines in DIC.

Characterization of the myosin-binding subunit of smooth muscle myosin phosphatase

A myosin phosphatase was purified from chicken gizzard smooth muscle. The holoenzyme is a trimer and consists of 130,000-, 38,000-, and 20,000-Da subunits (in agreement with the results of Alessi et al.: Alessi, D., MacDougall, L. K., Sola, M. M., Ikebe, M., and Cohen, P. (1992) Eur. J. Biochem. 210, 1023-1035). The catalytic subunit, 38,000 Da, is the type 1 delta isoform, and its derived amino acid sequence is identical to the rat isoform. The larger subunit bound to myosin and also interacted with the catalytic subunit. cDNA clones encoding the large subunit were isolated from chicken gizzard cDNA libraries. Overlapping clones indicated the presence of two isoforms, and open reading frames of 2889 and 3012 bases were obtained. These encoded proteins of 963 and 1004 amino acids, with masses of 106,700 and 111,600 Da, respectively. The insert in the larger isoform is in the center of the molecule, at residues 512-552. The N-terminal third of the molecule is composed of eight repeat sequences, similar to the cdc10/SWI6 or ankyrin repeat. Myosin binding and binding to the catalytic subunit are properties of a 58,000-Da fragment that represents the N-terminal part of the molecule.

beta 2-Glycoprotein I reactivity of monoclonal anticardiolipin antibodies from patients with the antiphospholipid syndrome

OBJECTIVE

To elucidate the specificity of anticardiolipin antibodies (aCL) from patients with the antiphospholipid syndrome (APS) to various phospholipids (PLs), DNA, and beta 2-glycoprotein I (beta 2-GPI).

METHODS

Five monoclonal aCL were established from peripheral blood lymphocytes of 3 patients with the APS. The reactivity of monoclonal aCL with various PLs, with DNA, and with beta 2-GPI was examined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

All of the monoclonal aCL bound to anionic PLs, only in the presence of beta 2-GPI. Neither monoclonal aCL nor beta 2-GPI bound to DNA. Monoclonal aCL bound to solid-phase beta 2-GPI on polystyrene ELISA plates that had carboxyl groups on their surface, but did not react with solid-phase beta 2-GPI on ordinary polystyrene plates. A mixture of beta 2-GPI and CL inhibited the binding of monoclonal aCL to beta 2-GPI, but CL or beta 2-GPI alone did not.

CONCLUSION

Monoclonal aCL may recognize a cryptic epitope, which appears as a result of beta 2-GPI binding to anionic PLs or to polystyrene with carboxyl groups.

Effects of TNF-alpha on hemodynamic changes and circulating endothelium-derived vasoactive factors in dogs

To elucidate the relation of tumor necrosis factor-alpha (TNF-alpha)-induced hemodynamic change to endothelium-derived vasoactive factors, we simultaneously measured hemodynamic parameters and circulating endothelin (ET)-1, ET-3, nitrite/nitrate (NOx), and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) in anesthetized dogs following administration of TNF-alpha with or without NG-nitro-L-arginine (L-NNA), a nitric oxide (NO) synthase inhibitor, and indomethacin, a cyclooxygenase inhibitor. Natural human TNF-alpha (10 micrograms/kg, n = 5) with or without L-NNA (1 mg/kg, n = 5) or indomethacin (2 mg/kg, n = 5) was administered intravenously as a bolus, while administration of vehicle served as control (n = 5). After administration of TNF-alpha, mean arterial pressure and cardiac index significantly decreased, whereas systemic (SVRI) and pulmonary (PVRI) vascular resistance index increased. Plasma levels of ET-1, ET-3, NOx, and 6-keto-PGF1 alpha significantly (P < 0.01) increased at 1 h. L-NNA or indomethacin blocked TNF-alpha-induced hypotension and remarkably increased SVRI but did not affect decreased cardiac index. Our data suggest that endogenous ET-1 may partly contribute to TNF-alpha-induced increases in SVRI and PVRI, against which ET-3, NO, and prostacyclin may function as compensatory vasodilators.