Generalized Degenerative Joint Disease in Osteoprotegerin (Opg) Null Mutant Mice.

Bone structure is modulated by the interaction between receptor activator of nuclear factor-κB (RANK) and RANK ligand (RANKL). Osteoprotegerin (OPG), a decoy receptor for RANKL, modifies osteoclast-mediated bone resorption directly and spares articular cartilage indirectly in rodents with immune-mediated arthritis by preventing subchondral bone destruction. The OPG/RANKL balance also seems to be critical in maintaining joint integrity in osteoarthritis, a condition featuring articular bone and cartilage damage in the absence of profound inflammation. The current study explored the role of OPG in sparing articular cartilage by evaluating joint lesions in adult C57BL/6J mice lacking osteoprotegerin (Opg (-) (/-)). At 3, 5, 7, 9, and 12 months of age, both sexes of Opg (-) (/-) mice developed severe degenerative joint disease (DJD) characterized by progressive loss of cartilage matrix and eventually articular cartilage. Lesions developed earlier and more severely in Opg (-) (/-) mice relative to age-matched, wild-type (Opg (+) (/+)), or heterozygous (Opg (+) (/-)) littermates (P ≤ .05). The femorotibial joint was affected bilaterally at 3 months, while other key weight-bearing diarthrodial joints (eg, coxofemoral, scapulohumeral, humeroradioulnar) were affected later and unilaterally. Cortical bone in subchondral plates and long bone diaphyses of Opg (-) (/-) mice but not Opg (+/+) or Opg (+) (/-) animals was osteoporotic by 3 months of age (P ≤ .05); the extent of porosity was less than the degree of DJD. Closure of the physes in long bones (P ≤ .05) and cartilage retention in the femoral primary spongiosa (P ≤ .05) affected chiefly Opg (-) (/-) mice. These data suggest that OPG plays an essential direct role in maintaining cartilage integrity in the articular surfaces and physes.

Anti-inflammatory and cartilage-protecting effects of an intra-articularly injected anti-TNF{alpha} single-chain Fv antibody (ESBA105) designed for local therapeutic use.

OBJECTIVES: (1) To show that a single-chain Fv antibody (scFv) against tumour necrosis factor alpha (TNFalpha) (ESBA105) has efficacy comparable to a full length anti-TNFalpha IgG (infliximab); (2) to evaluate whether ESBA105 has all the properties required for the local treatment of arthritis; and (3) to investigate its discriminative tissue penetration properties. METHODS: In vivo efficacy was measured in arthritis of the knee joint induced by the intra-articular injection of recombinant human TNFalpha (rhTNFalpha) in Lewis rats. Cartilage penetration of scFv (ESBA105) and full length IgG (infliximab) were studied in bovine cartilage specimens ex vivo. Tissue penetration, biodistribution and pharmacokinetics of ESBA105 were followed and compared after intra-articular and intravenous administration. RESULTS: In cell culture, ESBA105 showed similar TNFalpha inhibitory potency to infliximab. In vivo, ESBA105 inhibited rhTNFalpha-induced synovial inflammation in rats with efficacy again comparable to infliximab. An 11-fold molar excess of ESBA105 over rhTNFalpha resulted in 90% inhibition of knee joint swelling, inflammatory infiltrates and proteoglycan loss from cartilage. In ex vivo studies of bovine cartilage, ESBA105 penetrated well into the cartilage whereas infliximab remained on the surface. In vivo, rapid penetration into the synovial tissue, cartilage and surrounding tissues was observed following intra-articular injection of [(125)I]-ESBA105 into the knee joint of rabbits. CONCLUSIONS: ESBA105 potently inhibits inflammation and prevents cartilage damage triggered by TNFalpha. In contrast to a full length IgG, ESBA105 also penetrates into cartilage and can be expected to reverse the TNFalpha-induced catabolic state of articular cartilage in arthritides.

Characterization of human lymphocyte derived chemotactic factors for mononuclear phagocytes--I. Production and detection.

Human peripheral blood mononuclear cells were isolated on a large scale by leukapheresis of either individual donors or pooled cell concentrates supplied by a local blood bank. Optimal conditions with respect to cell density, lectin (soluble and insoluble Concanavalin A; phytohemagglutinin) concentration and culture time were established for monocyte chemotactic factor (LMCF) production. LMCF was assayed on highly purified human monocytes/macrophages which had been kept in culture up to 4 days for optimal expression of response to LMCF. Chemotaxis assays were performed in a novel type multichamber assembly and migrated cells were enumerated by enzyme-linked immunosorbent assay. Based on the described methodology it is possible to produce litre quantities of LMCF and assay large numbers of samples both of which are prerequisites for chemical and functional characterizations of LMCF.

Collection of large quantities of mononuclear cells from individual donors by continuous flow centrifugation leukapheresis.

Continuous flow centrifugation leukapheresis allows the continuous removal of leukocytes from the peripheral blood of individual donors. With the IBM 2997 cell separator, leukapheresis of granulocytes has been well established. On the other hand, no standard procedure for the collection of lymphocytes and/or monocytes has yet been described. Here, we investigated the conditions necessary for collection of large amounts of mononuclear cells with highest possible purity. The average yield from more than 100 healthy donors was 8 X 10(9) leukocytes per donor containing 80-100% mononuclear cells (MNC). Of the MNC, 10-55% were monocytes and 45-90% lymphocytes, depending on the donor. The rotor speed for maximal MNC collection was between 800 and 1000 rpm. Highest yields of monocytes were obtained at 900 rpm. No sedimenting agents were added to the blood. With more than 150 donors no rebound leukocytosis or lasting depression of blood cell counts was observed after leukapheresis. One patient with the Sézary syndrome who was subjected to leukapheresis for 26 months at 3-6 week intervals showed no pathological changes in his blood cell count to date. The disease was stabilized and no abnormalities in resistance to infection became apparent.

Purification of human blood monocytes by hypotonic density gradient centrifugation in Percoll.

Leukocyte cell concentrates, obtained by continuous flow leukapheresis from single donors, were separated on a continuous hypotonic (260 mosM) Percoll gradient. On average, 86% of monocytes were recovered in a sharp band at a purity of up to 91% (average 76%). By this procedure 1-2 X 10(9) monocytes may be obtained from an individual donor. Hypotonic gradient purification, as compared with isotonic (295 mosM) conditions, proved superior with regard to capacity, speed of performance, yield and monocyte purity.

Infection, autoimmunity and autoimmune disease.

Studies of the immune response of mammals to infectious agents have revealed that members of the hsp60 and hsp 70 family are highly immunodominant. Given their high conservation during evolution this was surprising, because of the apparent risk of triggering of autoimmunity and autoimmune disease during the defense of a mammal against infection. However, detailed studies of the immune responses to HSP in models of autoimmune diseases in animals resulted in a change of the view that autoimmunity necessarily leads to autoimmune disease. It has been found that modulation of autoimmunity to HSP is one way to prevent autoimmune disease. At least in some cases even treatment of autoimmune diseases by immunization with heat shock protein appears feasible. This was shown in adjuvant arthritis in Lewis rats and insulin dependent diabetes in NOD mice. Hsp60 and hsp70 are ubiquitous proteins. Their involvement in regulatory loops of autoimmunity may serve as basis for the development of strategies, to prevent and/or treat autoimmune diseases even without knowledge of the causative (auto-)antigen.

Use of a multiwell assembly for chemotaxis and evaluation by enzyme-linked immunosorbent assay (ELISA).

A multiwell chamber assembly for chemotaxis tests was designed, which integrates the established microtiter system. A microtiter plate is covered with a plastic plate containing up to 96 holes of the diameter of the microtiter wells. Between the plates, a Nucleopore filter sheet (5 micron) and a silicon rubber gasket is placed. As a model system, human monocytes and lymphocyte-derived chemotactic factors were used. As it was observed that monocytes migrate through the membrane and settle on the bottom of the microtiter wells, an ELISA was adapted for quantitation of cells. After washing and incubation with a xenoantiserum against human monocytes, the bound antibody was quantitated using protein-A-conjugated alkaline phosphatase and p-nitrophenyl phosphate as detection system. The plates were read in a multichannel photometer. Cell numbers were determined directly from a calibration curve established before with varying numbers of monocytes. Current experience allows the following conclusions: The chemotaxis test in microtiter plates is simpler, faster and uses less material than conventional Boyden chambers. Evaluation by ELISA is much faster and more accurate than by microscopy.

A constitutive 65 kDa chondrocyte protein as a target antigen in adjuvant arthritis in Lewis rats.

The autoantigen in adjuvant arthritis in Lewis rats is still unknown despite the knowledge that the 65 kDa mycobacterial heat-shock protein (hsp) is involved in the disease process. T cells and antibodies obtained from rats with adjuvant arthritis respond to chondrocyte membrane antigen(s). In Western blots a 65 kDa chondrocyte membrane protein (CH65) is stained by sera from arthritic rats. In addition, spleen cells from rats with adjuvant arthritis proliferate in vitro to chondrocyte membranes and CH65 as antigens. Furthermore, pretreatment of rats with CH65 or mycobacterial hsp65 but not human hsp60, induces a significant retardation of the onset of adjuvant arthritis in Lewis rats. The data suggest that CH65 is a potential autoantigen involved in the pathogenesis of adjuvant arthritis in Lewis rats.

Development of a novel, nonimmunogenic, soluble human TNF receptor type I (sTNFR-I) construct in the baboon.

Pharmacokinetics and immunogenicity of six different recombinant human soluble p55 tumor necrosis factor (TNF) receptor I (sTNFR-I) constructs were evaluated in juvenile baboons. The constructs included either an sTNFR-I IgG1 immunoadhesin (p55 sTNFR-I Fc) or five different sTNFR-I constructs covalently linked to polyethylene glycol. The constructs were administered intravenously three times, and pharmacokinetics and immunogenicity were examined over 63 days. All of the constructs were immunogenic, with the exception of a 2.6-domain monomeric sTNFR-I. To evaluate whether the nonimmunogenic 2.6-domain monomeric construct could protect baboons against TNF-alpha-induced mortality, baboons were pretreated with 1, 5, or 10 mg/kg body wt and were compared with baboons receiving either placebo or 1 mg/kg body wt of the dimeric 4.0-domain sTNFR-I construct (n = 3 each) before lethal Escherichia coli bacteremia. The monomeric construct protected baboons and neutralized TNF bioactivity, although greater quantities were required compared with the dimeric 4.0-domain sTNFR-I construct. We conclude that E. coli-recombinant-derived human sTNFR-I constructs can be generated with minimal immunogenicity on repeated administration and still protect against the consequences of exaggerated TNF-alpha production.

An assay for the detection of interleukin-1 synthesis inhibitors: effects of antirheumatic drugs.

The monokines interleukin-1 beta and alpha (IL-1) play a central role in the connective tissue destruction of many chronic inflammatory diseases. A high capacity screening assay for the detection of inhibitors of IL-1 biosynthesis has been established. Normal human monocytes were obtained by leukapheresis and elutriation. IL-1 beta and alpha biosynthesis was stimulated with LPS, and cell-associated and secreted IL-1 beta and IL-1 alpha were measured by specific immunoassays (ELISA). The mean total IL-1 beta (cell-associated and secreted) production in 18 different donors was 11 ng/10(6) cells (range 1.2-28.8). Secreted IL-1 beta represented 31 to 86% of the total IL-1 beta. More IL-1 alpha than IL-1 beta was produced but, unlike IL-1 beta, IL-1 alpha was poorly secreted. The steroids prednisolone and dexamethasone, gold (sodium aurothiomalate) and chloroquine were potent inhibitors of the IL-1 production. Mean IC50 values of 180 nM (range 2.5 nM-1 microns), 10 microM (range 6-20 microM) and of 75 microM were found for prednisolone, gold and chloroquine, respectively. Above 5 microM, the non-steroidal anti-inflammatory compounds indomethacin and BW755C increased IL-1 beta biosynthesis. Nordihydroguaiaretic acid inhibited the level of the secreted form of IL-1 beta, but tended to increase the cell-associated level. D-Penicillamine (up to 6 mM), cyclosporin A (up to 1 microM) and methotrexate (up to 12 microM) inhibited neither cell-associated nor secreted IL-1 beta levels. This high capacity assay, which is insensitive to classical NSAIDs, may serve in the detection and characterization of new classes of anti-inflammatory compounds.

Arthritis induced by continuous infusion of hr-interleukin-1 alpha into the rabbit knee-joint.

Continuous infusion of 200 ng/day hrIL-1 alpha for 14 days into knee-joints of rabbits leads to a severe arthritis of low aggressivity. This arthritis shows simultaneously characteristics of acute (serous and fibrinous exudation, polymorph infiltration, etc.) as well as chronic (synovial cell proliferation and fibrosis, pannus formation, cartilage and bone erosion, etc.) inflammation. The arthritis was associated with a distinct loss of metachromasia of the articular cartilage. These results indicate that IL-1 might play an important role in the induction and maintenance of arthritis.

Arthritis in MRL/LPR mice and in collagen II sensitized DBA-1 mice and their use in pharmacology.

For assessment of anti-arthritic drugs, we used mice of the autoimmune MRL/lpr strain and DBA-1 mice sensitized with collagen type II. Our studies showed that in these two mouse arthritis models, unlike the classical rat adjuvant arthritis, the nonsteroidal antiinflammatory compounds tested were either ineffective or minimally affected a chosen number of humoral parameters and the incidence and severity of arthritis. Interestingly, both arthritis models showed a distinct pharmacological pattern in response to the slow-acting anti-rheumatic drugs, whereas steroids and cyclophosphamide inhibited both arthritic processes. Therefore, these two mouse models are useful for studying the immunopathological events operating in chronic inflammation and could potentially serve the characterization of new antirheumatic drugs.

The lipopolysaccharide of escherichia coli C- studies on the anomeric configurations of the hexoses in the R1 core.

Lipopolysaccharide from E, coli C as well as lipopolysaccharides from submutants of E. coli with incomplete core structures in their lipopolysaccharides were isolated and quantitatively analyzed. Core oligosaccharides were isolated from lipopolysaccharides by acetic acid degradation and were purified by gel chromatography. The difference in molecular rotations of the core oligosaccharides from E. coli C and 6 submutants thereof with incomplete core structure were correlated to the differences in sugar compositions. The anomeric configurations have been deducted from the high or low contribution of each individual sugar to the molecular rotation of the core oligosaccharide from E. coli C. The primary structure of the hexose region of the lipopolysaccharide from E. coli C is primary structure of the hexose region of the lipopolysaccharide from E. coli C is, see formula in text. The anomeric configurations of glucoses I, II, and III were confirmed by precipitation reactions of alkali treated lipopolysaccharides from E. coli C, C23. 1, and C21 with Concanavalin A. The alpha-anomeric configurations of both the galactoses were confirmed by degradation studies with alpha-galactosidase (E.C.3.2.1.22) from green coffee beans with the isolated and purified core oligosaccharide from E. coli C71.

Duration of bone protection by a single osteoprotegerin injection in rats with adjuvant-induced arthritis.

Daily osteoprotegerin (OPG) injection for 7 or more days prevents bone loss for 3 weeks in rats with adjuvant-induced arthritis (AdA). The present experiments defined the duration of bone protection in AdA provided by a single OPG bolus. Male Lewis rats received OPG at the onset or peak of clinical disease, after which bone mineral density (BMD), erosions, and osteoclasts were evaluated. An OPG bolus (4 mg/kg subcutaneously) at onset eliminated osteoclasts, preserved BMD for 7 days, and prevented bone erosions for 4 days. In contrast, an OPG bolus (1, 3, 10, or 30 mg/kg intravenously) given at the peak of disease eradicated osteoclasts in a dose-dependent manner but had no impact on bone integrity due to extensive pre-existing bone loss. These data indicate that one OPG injection will inhibit joint erosions for several days, and confirm that bone-sparing therapy must be initiated early in disease to protect joint integrity.

Phosphate localization in carbohydrates - a study on enterobacterial lipopolysaccharides.

The localization of the phosphate substituents in the core oligosaccharide of the lipopolysaccharides of Enterobacteriaceae has been reported for Salmonella minnesota and Escherichia coli B only. In these cases the localizations were done by a beta-elimination reaction in mild alkaline solution after periodate oxidation. We report now on a method generally applicable on carbohydrates. The localization of phosphate groups and the extent of substitution with phosphate residues in carbohydrates can be determined by the following reaction sequence: methylation, dephosphorylation, and reetherification (labelling) with C2H3J or C2H5J followed by derivatizing to partially methylated alditol acetates and analysis by combined gas liquid chromatography/mass spectrometry. The results presented here are obtained by application of this method to isolated core oligosaccharides of lipopolysaccharides from E. coli C23.1, E. coli C71, E. coli F2515, and P. mirabilis R4/O 28. Phosphate is localized at C-4 of the chain heptoses in the lipopolysaccharides of E. coli C and E. coli R4, and at C-7 of the branching heptose in the lipopolysaccharide of P. mirabilis R4/O 28.

Dexamethasone enhances CTLA-4 expression during T cell activation.

T cell activation is enhanced by the costimulatory interaction of B7 on antigen-presenting cells and CD28 on T cells, resulting in long-term T cell proliferation, differentiation and production of large amounts of cytokines, such as interleukin (IL)-2. CTLA-4 is a co-stimulation receptor that shares 31% homology with CD28 and binds B7 family members with higher affinity. CTLA-4 is transiently expressed intracellularly and on the cell surface following activation of T cells. We have studied the kinetics of CTLA-4 expression and the effects of dexamethasone on CTLA-4 expression during T cell activation in cultures of mouse spleen cells stimulated by a mixture of immobilized anti-CD3 and anti-CD28 monoclonal antibodies (anti-CD3/CD28 mAb) or concanavalin A (ConA). CTLA-4 expression peaked on day 2 and returned to background levels after 7 days. Dexamethasone was found to potentiate CTLA-4 expression in a dose-dependent manner with an EC50 effective concentration 50%) of about 10(-8) M. In contrast, other immunosuppressive agents, such as rapamycin or cyclosporin A had no or an inhibitory effect on CTLA-4 expression, respectively. Dexamethasone also stimulated CD28 expression, but inhibited IL-2R expression during anti-CD3/CD28 mAb-induced mouse splenic T cell activation. Western blot analyses of lysates of activated mouse T cells showed that dexamethasone increased CTLA-4 protein levels twofold during anti-CD3/CD28 mAb-induced activation. Dexamethasone also enhanced CTLA-4 messenger RNA twofold as quantified by ribonuclease protection assay. The effects of dexamethasone on CTLA-4 expression were glucocorticoid-specific and completely inhibited by the glucocorticoid receptor antagonist mifepristone (RU486), indicating that the effect of dexamethasone on CTLA-4 expression is mediated through the glucocorticoid receptor. In conclusion, the immunosuppressive agent dexamethasone actually stimulates CTLA-4 expression, which is involved in downregulation of T cell activation.

Interactions of micromolar concentrations of fluoride with Streptococcus rattus FA-1.

Inhibition of the metabolic activities of bacteria by trace amounts of fluoride is manifested phenomenologically as changes in the pH gradient and/or the electrical potential between the cellular interior and the surrounding medium. These data were obtained from the intracellular/extracellular distribution of radioactivity labelled fluoride (18F), 5,5-dimethyloxazolidine-2,4-dione (14C), and tetraphenylphosphonium chloride (14C). When taken up from acidic media, trace concentrations of fluoride (1-100 microM) reduce the intracellular/extracellular pH gradient and affect the electrical potential across the cell membrane. The chromatographic fractionation of fluoride-charged bacterial homogenates showed that fluoride is attached to many proteins of the cytoplasm, the cell membrane, and to nonproteinaceous components of the cell wall. Lysozyme treatment synergistically affects the vulnerability of the bacteria to micromolar concentrations of fluoride.