Biomedical subjects

B Gilburd

Publications and source records attributed to B Gilburd.

At least 55 records · Page 3Linked to original sources

PubMed1998

Characterization of murine monoclonal anti-endothelial cell antibodies (AECA) produced by idiotypic manipulation with human AECA.

The IgG fraction of human anti-endothelial cell antibodies (AECA) obtained from a patient with Wegener's granulomatosis was used as immunogen to raise AECA mAb in mice selected among those which developed vasculitis-like lesions after immunization. Three mAb (BGM, 3C8 and 7G2), selected by cyto-ELISA and flow cytometry analyses, featured a specific reactivity with human umbilical vein endothelial cells (HUVEC) and the mouse endothelial cell line H5V; on the contrary, HEp2 cells, the murine melanoma B16 cell line, the extracellular matrix as well as several other antigens tested were not recognized. BGM mAb, an IgG3 precipitating a 70 kDa structure from HUVEC, was able to induce endothelial cells to secrete amounts of IL-6 significantly higher than irrelevant controls or mAb binding different endothelial antigens (i.e. CD31, CD29, ICAM-1 and HLA class I). BGM mAb induced significant levels of antibody-dependent cell cytotoxicity (13 +/- 2.5 versus 0.6 +/- 0.03%). To the best of our knowledge, BGM is the first murine mAb specific for human endothelial cells generated by idiotypic manipulation; secondly, its biological properties further support the notion of a pathogenic role for AECA in autoimmune-mediated diseases.

Animals↗

PubMed1998

Immunomodulation of murine experimental SLE-like disease by interferon-gamma.

The objective of this study was to assess the impact of murine recombinant IFN-gamma and anti-IFN-gamma monoclonal antibody on the BALB/c mice experimental model of lupus. BALB/c female mice were immunized with a human anti-DNA antibody that carries the 16/6 idiotype. These mice were divided into several therapeutic groups according to different treatment strategies; injection with mouse recombinant IFN-gamma, anti-IFN-gamma mAb, phosphate-buffered saline (PBS), irrelevant mouse IgG and control groups that were neither treated nor immunized with the human anti-DNA antibody. The administration of IFN-gamma, intensified the degree of clinical, histological and serological parameters in this model of BALB/c murine lupus. This immunomanipulation decreased the mice longevity. All the laboratory parameters reflected acceleration of the disease in the IFN-gamma treated group as an elevated sedimentation rate, decreased white blood cell count and the development of massive proteinuria. One month after the boost injection, all the mice that were immunized with the anti-DNA antibody, developed high titers of autoantibodies; however, following an additional month, their levels declined in the IFN-gamma treated group. These findings were in concordance with an increased glomerular deposition of immune complexes in the IFN-gamma treated mice. IFN-gamma upregulated the levels of IL-4 and increased the number of IL-4 and IL-6 secreting splenocytes. In conclusion IFN-gamma administration can aggravate the clinical and laboratory outcome of 16/6 id induced lupus in BALB/c mice.

Animals↗

PubMed1997

Anti-neutrophil cytoplasmic antibody-enriched IgG induces adhesion of human T lymphocytes to extracellular matrix proteins.

Recent studies have shown that anti-neutrophil cytoplasmic antibodies (ANCA) can activate neutrophils to adhere to endothelium, degranulate, and cause endothelial cell injury. These data have lead to the hypothesis that the T cell inflammatory response causing the vasculitis in Wegener's granulomatosis (WG) is secondary to stimulation of neutrophils by ANCA. So far there is no evidence for a direct effect of ANCA on lymphocytes. The present study was designed to examine whether lymphocytes can be directly stimulated by ANCA to adhere to endothelial extracellular matrix (ECM) proteins. Human and mouse ANCA-enriched IgG were tested for their ability to increase adhesion of human T lymphocytes to fibronectin, laminin, and intact ECM. Incubation of human T lymphocytes with human ANCA-enriched IgG increased adhesion of the lymphocytes in a dose-dependent manner to fibronectin, laminin, and intact ECM (the percentage adhesion to intact ECM was 55.7 +/- 3.1 and 45.0 +/- 1.0% for lymphocytes incubated with human IgG containing ANCA or control human IgG, respectively; P = 0.0045). The same induction of adhesion to fibronectin, laminin, and intact ECM was observed when the cells were incubated with the F(ab)2 fragment of ANCA-enriched IgG. Similarly, ANCA-enriched IgG produced in mice increased the adhesion of lymphocytes to fibronectin (the percentage adhesion to fibronectin was 29.7 +/- 4.3 and 16.6 +/- 1.9% for lymphocytes incubated with mouse IgG-ANCA or control mouse IgG, respectively; P = 0.0008). These results may suggest that ANCA can directly stimulate lymphocytes to adhere to endothelial ECM and to induce the vasculitic lesions of WG. It remains to be shown by which mechanisms ANCA stimulate lymphocytes to adhere to ECM.

Animals↗

PubMed1997

Antiperinuclear factor--clinical, serological and genetic correlates in Israeli patients with rheumatoid arthritis.

The possible association between the presence of antiperinuclear factor (APF) and clinical and genetic parameters was investigated in 54 Israeli patients with rheumatoid arthritis (RA). Rheumatoid factor (RF) was detected in the sera of 43 patients (80%) and APF was positive in 33 (61%). No significant statistical differences were found in the presence of HLA-DR4 and/or DR1 between APF-positive and -negative patients. Furthermore, neither the Ritchie articular index nor the patient's functional class correlated with the presence of APF. The results of our study suggested that although Israeli patients have a different genetic background, the presence and behaviour of APF is similar to that of other Caucasian populations.

Adult↗

PubMed1997

Immunologic characterization and functional properties of murine antibodies raised against deleted mutants of human beta 2-glycoprotein I.

beta 2-Glycoprotein I (beta 2GPI) is a 50 kDa molecule proposed as a principal target of 'autoimmune' antiphospholipid antibodies (aPL). We have used deleted mutants (DM) representing different domains of beta 2GPI (I-IV, IV-V and V) for immunization of naive mice and studied the characteristics of the respective murine IgG preparations in comparison with affinity-purified IgG from two patients with primary antiphospholipid syndrome. Immunization with beta 2GPI and with the DM produced anti-beta 2GPI antibodies, part of which reacted with negatively charged phospholipids (PL), whereas reactivity with cardiolipin was evident only in the IgG from mice immunized with beta 2GPI. These results are consistent with the presumption that aPL are induced following the in vivo association of beta 2GPI (used for immunization) with resident negatively charged PL. Accordingly, DM which either lack the PL binding site or aPL attachment locus did not elicit, upon immunization, antibodies reactive with PL. Further, murine anti-beta 2GPI IgG and human 'autoimmune' aPL were similar, albeit not identical, in terms of DM requirement for PL binding and charge dependency. Murine antibodies and human aPL, regardless of their binding characteristics, were found to bind significantly to platelets upon their activation with thrombin and to promote platelet activation. The results of the current study emphasize the dissimilarities between human 'autoimmune' aPL and murine anti-beta 2GPI. Thus, anti-beta 2GPI antibodies to different DM as well as human aPL are capable of binding and activating human platelets provided beta 2GPI is present.

Animals↗

PubMed1997

'Autoantibody dominance' pattern following idiotypic manipulation of naive mice by immunization with anti-U1RNP antibodies.

OBJECTIVE: To study the immune response and clinical findings in mice immunized with different epitope-specific anti-U1RNP antibodies purified from the sera of mixed connective tissue disease (MCTD) patients with various clinical manifestations. METHODS: BALB/c mice were immunized with anti-U1RNP-IgG preparations from 3 patients with MCTD. Group 1 was immunized with U1 70 kD A-positive IgG, group 2 with U1 70 kD-negative, U1A, U1C, B-B'-positive IgG and group 3 with U1 70 kD, U1A, U1C-positive IgG. The induced autoantibody response in the mice was studied by ELISA and immunoblots and the clinical findings of MCTD in humans were assessed. RESULTS: Immunoblot assays showed that mice immunized with different human anti-U1RNP antibodies developed predominantly autoantibodies directed against U1 68-70 kD epitope. This 'autoantibody dominance' pattern was not associated with clinical findings. CONCLUSIONS: The restricted murine autoimmune response may provide clues to the diversified autoantibody production in autoimmune diseases and explain in part the changing patterns of clinical findings in individuals with MCTD.

Animals↗

PubMed1997

The emerging concept of pathogenic natural autoantibodies.

Natural autoantibodies (NAA) are self-reacting antibodies found in the serum. NAA do not require antigenic or mitogenic stimuli for their synthesis. These low affinity antibodies are found in the sera of normal healthy subjects and animals and are thought to constitute part of the innate immunity by providing a first line of defense against foreign invading pathogens. In this paper we summarize the recently accumulated data which points to the pathogenic potential of NAA, challenging the paradigm of nonharmful antibodies.

Animals↗

PubMed1997

Atherosclerosis in LDL-receptor knockout mice is accelerated by immunization with anticardiolipin antibodies.

Atherosclerosis is a process initiated by accumulation of macrophages in distinct areas of endothelial cell damage and uptake of large amounts of lipids. Recently, it has been shown that the immune system plays an active part in the progression of the atherosclerotic plaque although its precise role has not yet been elucidated. Anticardiolipin antibodies (aCL) are generally found in the sera of patients with the antiphospholipid syndrome (APS) and are associated with a prothrombotic state. Several authors have demonstrated that aCL can activate platelets and endothelial cells as well as increase oxidized low density lipoprotein (LDL) uptake by macrophages. In the present study we sought to assess the effect of immunization with aCL (Ab1, leading to the production of mouse aCL-Ab3) on the progression of atherosclerosis. Two groups of 8-weeks old female LDL-receptor knockout mice (n = 13 per group) were immunized with IgG purified from the serum of an APS patient or with normal human IgG, respectively. The aCL immunized mice developed high titres of 'self' aCL (detected using the standard aCL ELISA) as compared with the normal human IgG immunized mice, whereas no differences were noted between both study groups with respect to the serum lipid levels. The extent of fatty streak formation was significantly higher in the aCL immunized mice in comparison with the human IgG injected mice (mean aortic lesion size of 5308 +/- 471 microns2 vs 1027 +/- 184 microns2, respectively, P < 0.01). The immunohistochemical analysis of the atherosclerotic plaques from both mouse groups did not display differences in cellular composition. The results of the study show that mouse aCL induced by immunization with human aCL from an APS patient enhance atherogenesis in LDL-RKO mice and imply that these antibodies may play a role in atherosclerosis development in patients with the APS.

Animals↗

PubMed1996

Pathogenic role of anti-endothelial cell antibodies in vasculitis. An idiotypic experimental model.

Idiotypic manipulation of naive mice has previously been used for induction of systemic autoimmune diseases (e.g., antiphospholipid syndrome, systemic lupus erythematosus, and Wegener's granulomatosis). The aim of this study focused on the utilization of this technique to induce the production of anti-endothelial cells Abs (AECA) and autoimmune vasculitis in a murine model. AECA were derived from a Wegener's granulomatosis patient's plasma. IgG was purified by absorption on a proteinase-3 affinity column resulting in the depletion of anti-neutrophil cytoplasmic Ab activity. The absorbed IgG fraction displayed a high titer of AECA as evidenced by a cyto-ELISA against unfixed human umbilical vein endothelial cells. BALB/c mice were actively immunized with the purified AECA. Three months after a boost injection with the human AECA, mice developed endogenous AECA (AB), but not Abs to proteinase-3, cardiolipin, or DNA. Histologic examination of lungs and kidneys revealed both lymphoid cell infiltration surrounding arterioles and venules; as well as deposition of Igs at the outer part of blood vessel walls. This experimental animal model of vasculitis, a product of our method of idiotypic manipulation, provides the first direct proof for the pathogenicity of AECA.

Animals↗

PubMed1996

Induction of thyroid autoantibodies in naive mice by idiotypic manipulation.

Previously, we have shown that it is possible to induce, in naive mice, systemic autoimmune diseases (e.g., antiphospholipid syndrome and systemic lupus erythematosus) by idiotypic manipulation. In the present study we expanded our experience to examine whether idiotypic manipulation could be utilized to induce organ-specific autoantibodies and a disease mediated by cellular mechanisms, namely, experimental autoimmune thyroiditis. Fifteen BALB/c mice were immunized with a monoclonal mouse anti-human thyroglobulin (hTg) antibody; controls were immunized with an irrelevant mouse IgG. The mice immunized with anti-hTg antibody developed, 6 weeks after immunization, autoantibodies to human thyroglobulin, but not to dsDNA, cardiolipin, or myeloperoxidase. The presence of specific autoantibodies was associated with low production of thyroid hormones, and during a follow-up of 20 weeks the mice did not develop characteristic histological signs of thyroiditis. We conclude that idiotypic manipulation can induce anti-thyroglobulin autoantibodies.

Animals↗

PubMed1996

Emerging cross-regulatory roles of immunity and autoimmunity in atherosclerosis.

Atherosclerosis is a histopathological process of a multifactorial origin. Whereas the genetic and biochemical causes received considerable attention, the involvement of the immune system has generally been considered negligible. In recent years evidence has been presented to support the dominant role played by the immune system in atherosclerosis. Two major antigenic determinants against which the immune response may be triggered have been suggested, namely the heat shock protein 60/65 and oxidized low density lipoprotein. The current paper reviews the data regarding the involvement of the immune system in atherogenesis with respect to the antigenic candidates mentioned above.

Arteriosclerosis↗

PubMed1996

Membranous nephropathy in primary antiphospholipid syndrome: description of a case and induction of renal injury in SCID mice.

Primary antiphospholipid syndrome (PAPS) is a recently recognized clinical entity encompassing the combination of thromboembolic phenomena, thrombocytopenia and recurrent abortions in the presence of antiphospholipid antibodies. We present a patient with PAPS accompanied by renal involvement, manifested as membranous nephropathy, as proven by a renal biopsy. To investigate further the possible association between PAPS and the renal lesions we attempted to induce similar renal manifestations by transferring peripheral blood lymphocytes (PBL) from this patient to severe combined immunodeficiency (SCID) mice. The mice transfused with PBL from the affected patient exemplified antiphospholipid antibodies (aPL) following which a renal lesion consistent with the human membranous nephropathy lesion was precipitated. This study substantiates the role of aPL as possible inducers of renal damage.

Adult↗

PubMed1995

Transfer of experimental antiphospholipid syndrome by bone marrow cell transplantation. The importance of the T cell.

OBJECTIVE: To investigate the potential of bone marrow cells from mice with primary antiphospholipid syndrome (APS) to transfer the disease to naive mice, and to determine the importance of the role of T cells in the APS. METHODS: Experimental primary APS was induced in naive mice following active immunization with anticardiolipin (aCL) monoclonal antibody (MAb). Whole-population or T cell-depleted bone marrow cells from mice with experimental primary APS were infused into total body-irradiated naive BALB/c recipients. RESULTS: Bone marrow cells (in the presence of T cells) had the potential to induce experimental APS in naive mice, which resulted in high serum titers of aCL, antiphosphatidylserine, and antiphosphatidylinositol antibodies; an increased number of antibody-forming cells specific for each of the above phospholipids; a positive lymph node cell proliferative response to aCL MAb; and clinical features of primary APS, including thrombocytopenia, prolonged activated partial thromboplastin time (indicating the presence of lupus anticoagulant), and a high frequency of fetal resorptions (the equivalent of human fetal loss). T cell-depleted bone marrow cells did not transfer the disease. CONCLUSION: This study demonstrates the important role of T cells in the development and transfer of experimental primary APS and raises the possibility of T cell manipulations in treatments to prevent this condition.

Animals↗

PubMed1995

Characterization of biologically active antineutrophil cytoplasmic antibodies induced in mice. Pathogenetic role in experimental vasculitis.

OBJECTIVE: To investigate the pathogenetic role of antineutrophil cytoplasmic antibodies (ANCA) in Wegener's granulomatosis (WG). METHODS: BALB/c mice were immunized with human IgG ANCA from a patient with WG. Control mice were immunized with normal human IgG. Levels of mouse ANCA and other autoantibodies were determined. Mouse ANCA were tested for their ability to induce adhesion and respiratory burst of neutrophils. The mouse lungs and kidneys were examined for the development of vasculitis. RESULTS: Mice immunized with human ANCA developed anti-human ANCA and anti-anti-human ANCA (mouse ANCA), while the controls did not develop these antibodies. Mouse ANCA were capable of inducing adhesion of neutrophils to fibronectin and activating the respiratory burst in neutrophils. Moreover, the mice that were immunized with human ANCA developed perivascular mononuclear cell infiltrates in the lungs, suggesting vasculitis. CONCLUSION: The results suggest a pathogenic role of ANCA in WG, and may imply that activation of neutrophils is the initiating event in the development of vasculitis in WG.

Animals↗

PubMed1995

Myelin- and microbe-specific antibodies in Guillain-Barré syndrome.

We surveyed the frequency of reported infections and target autoantigens in 56 Guillain Barré syndrome (GBS) patients by detecting antibodies to myelin and microbes. Sulfatide (43%), cardiolipin (48%), GD1a (15%), SGPG (11%), and GM3 (11%) antibodies were the most frequently detected heterogenous autoantibodies. A wide spectrum of antimicrobial IgG and IgM antibodies were also detected; mumps-specific IgG (66%), adenovirus-specific IgG (52%), varicella-zoster virus-specific IgG (46%), and S. pneumoniae serotype 7-specific IgG (45%) were the most prevalent. Our results indicate that polyclonal expansion of physiologic and pathologic antibodies and/or molecular mimicry likely occurs following infection and is related to other autoimmune factors in the etiology of GBS. Although no single definitive myelin-specific autoantibody was identified, our results suggest a unique pattern of reactivity against autoantigens.

Adolescent↗

PubMed1995

Absence of anti-idiotypic antibodies in IVIG preparations to autoantibodies of rare autoimmune diseases.

Intravenous immunoglobulins (IVIG) were found to contain anti-idiotypic antibodies against autoantibodies of various autoimmune diseases. We examined commercial IVIG preparations, from three different manufactures, for the presence of autoantibodies and anti-idiotypic antibodies of two rare autoimmune diseases--primary biliary cirrhosis [anti-pyruvate dehydrogenase (PDH) antibodies] and Goodpasture's syndrome (anti-NC1 antibodies). We used ELISA studies as well as immunoblotting and anti-PDH enzyme activity for the detection of anti-PDH antibodies. ELISA and immunofluorescence studies were used for the detection of anti-NC1 antibodies. The presence of anti-idiotypic activity against anti-PDH fragments on Sepharose-bound IVIG [F(ab)2]. Anti-anti-NC1 activity was evaluated employing inhibition ELISA and immunofluorescence studies. The commercial IVIG preparations that were examined did not contain anti-PDH or anti-NC1 antibodies nor anti-idiotypic activity against these autoantibodies. We conclude that commercial IVIG may lack anti-idiotypic activity against rare autoantibodies.

Anti-Glomerular Basement Membrane Disease↗

PubMed1995

Natural autoantibodies in sera of patients with Gaucher's disease.

Gaucher's disease (GD) is associated with hyperactivity of the immune system, which manifests by polyclonal hypergamma-globulinemia and an increased incidence of monoclonal gammopathies in GD patients. We analyzed sera of 43 patients with GD for the presence of autoantibodies against 14 autoantigens. The results demonstrated a significant increase in the incidence of all autoantibodies tested, ranging from 11% for anti-RNP, pyruvate dehydrogenase (PDH), and DNA antibodies to 57% for rheumatoid factor. The autoantibodies were of all three isotypes, namely, IgG, IgM, and IgA. There was no correlation between the levels of immunoglobulins in the serum and the titer of autoantibodies found. Immunization of naive mice with a pool of purified anti-DNA antibodies form GD patients did not result in induction of experimental systemic lupus erythematosus (SLE), suggesting that they may represent natural autoantibodies that are not pathogenic. In conclusion, we found high titers of natural, polyspecific, nonpathogenic autoantibodies in the sera of GD patients.

Adolescent↗

PubMed1995

Induction of Goodpasture antibodies to noncollagenous domain (NC1) of type IV collagen in mice by idiotypic manipulation.

The characteristic pathogenic autoantibodies in Goodpasture's syndrome (GPS) are directed to the noncollagenous domain (NC1) of basement membrane type IV collagen. To examine whether immunization with anti-NC1 antibodies could lead to GPS-like pathology, naive BALB/c mice were immunized intradermally with a mouse IgG anti-NC1 monoclonal antibody or IgG serum fraction derived from patients with GPS. Mice immunized with normal mouse or human IgG and nonimmunized mice served as controls. Anti-NC1 antibodies of IgG isotype were detected in the sera of mice injected with anti-NC1 antibodies, but not in the sera of control mice. The presence of circulating anti-NC1 antibodies coincided in some of the mice erythrocyturia or proteinuria and pathological changes in the kidneys. No pathologic alterations were seen in the control mice. The results show that specific idiotypic manipulation can induce anti-NC1 antibodies and pathological changes resembling human GPS.

Animals↗