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Biomedical subjects

R I Fox

Publications and source records attributed to R I Fox.

At least 73 records · Page 4Linked to original sources
PubMed1990

Epstein-Barr virus induces aggressive lymphoproliferative disorders of human B cell origin in SCID/hu chimeric mice.

C.B-17 scid mice were reconstituted by intraperitoneal injection of human tonsil cells or PBL from EBV-seronegative donors. Subsequent injection of EBV resulted in the rapid development (within 19-33 d) of aggressive, fatal, lymphoproliferative disorders of human B cell origin. Autopsies revealed solid tumors in the abdomen, and occasionally in the liver, thymus, or spleen. Histopathologic analysis showed that the tumors were high-grade immunoblastic lymphomas and FACS analyses of tumor cells indicated that they were of human B-lymphoid origin. The tumor cells grew in vitro and induced new tumors on injection into severe combined immunodeficient (SCID) mice. Karyotypic analysis and Southern blots for c-myc or bcl-2 rearrangements revealed no chromosomal abnormalities and translocations. Southern blot analysis also showed that the cells possessed EBV DNA sequences. Although these tumors undoubtedly reflect infection of the transferred B cells with EBV in vivo, intraperitoneal transfer of short-term lymphoid cell lines transformed in vitro with EBV resulted in ascites production without evidence of tumor formation.

Animals↗
PubMed1990

Sjögren's syndrome and primary biliary cirrhosis: presence of autoantibodies to purified mitochondrial 2-OXO acid dehydrogenases.

Sjögren's syndrome is well known for the presence of antibodies directed at specific nuclear antigens. However, the presence of antibodies reacting with a variety of other self antigens, including antimitochondrial antibodies, has often been reported although their significance is unknown. Moreover, patients with Sjögren's syndrome have been occasionally reported to be concordant with primary biliary cirrhosis. To address this issue we studied in a group of 96 patients with Sjögren's syndrome the presence of autoantibodies to the dihydrolipoamide acetyltransferases of both pyruvate dehydrogenase and branch chain ketoacid dehydrogenase and to alpha-ketoglutarate dehydrogenase; these latter enzymes are the mitochondrial target antigens of primary biliary cirrhosis. We report that 7 of the 96 patients reacted with the mitochondrial antigens that are prominent in primary biliary cirrhosis. Moreover, in those patients showing reactivity with mitochondrial antigens, the autoantibodies were directed at the same immunodominant epitopes that have been previously characterized in primary biliary cirrhosis. One of the 7 positive patients was known to have primary biliary cirrhosis. We hypothesize that the remaining 6 patients are at clinical risk for the development of primary biliary cirrhosis and/or that abnormalities would be found on liver biopsy.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1989

Molecular characterization of a major autoantibody-associated cross-reactive idiotype in Sjogren's syndrome.

Primary Sjogren's syndrome is an autoimmune disorder characterized by lymphocytic infiltration of the salivary and lacrimal glands, producing associated dry eyes (keratoconjunctivitis sicca), dry mouth, and intermittently swollen salivary glands. A high proportion of the infiltrating B lymphocytes express surface and cytoplasmic Ig bearing a kappa-L chain-associated CRI defined by reactivity with the murine mAb, 17.109. To determine the structural basis for CRI expression in this disease, we generated CRI+ lymphoblastoid cell lines and a cDNA library from lymphocytes extracted from Sjogren's syndrome patients' salivary gland biopsy specimens. Nucleic acid sequence analyses of the mRNA of one such 17.109-CRI+ lymphoblastoid cell line (NOV) reveals the expressed kappa light chain variable region gene (V kappa gene) to be homologous to Humkv325, a conserved V kappa gene used at relatively high frequency in certain B cell malignancies. In addition, synthetic oligonucleotides, corresponding to the first and third frameworks and the second complementarity determining region of the Humkv325 gene, were used to identify and isolate clones from a cDNA library generated from SS salivary gland lymphocytes. Clones annealing specifically with one or more of these oligonucleotide probes contained kappa light chain cDNA. The sequences corresponding to the variable region of two clones (Taykv320 and Taykv306) were homologous to Humkv325. The V kappa genes of four other cDNA clones (Taykv322, Taykv310, Taykv308, and Taykv312) most likely were generated somatically from the rearranged Humkv325 gene through a limited number of nucleic acid base substitutions. Our results suggest that the high frequency of 17.109-CRI expression in Sjogren's syndrome patients results from a multiclonal expansion of B cells using Humkv325, and that the expressed Humkv325 may undergo somatic diversification in an apparent Ag-driven response.

Amino Acid Sequence↗
PubMed1989

Detection of Epstein-Barr virus DNA by polymerase chain reaction in blood and tissue biopsies from patients with Sjogren's syndrome.

Polymerase chain reaction has been used to detect increased levels of EBV DNA in salivary gland (SG) biopsies and PBL from patients with Sjogren's syndrome (SS). These results suggest that EBV, which has a normal site of latency in a small number of SG epithelial cells, may be reactivated in SS patients and provide a target for immune attack. The great sensitivity of polymerase chain reaction (PCR) and the ability to analyze very small tissue biopsies (37) make this technique well suited for clinical diagnosis. Specific methods to prevent artefactual contamination of tissue biopsy DNA with viral DNA of other samples (i.e., lyophilization of samples before DNA extraction) and the use of an internal positive control (i.e., inclusion of primers for a single copy human gene) during PCR amplification are presented. Since EBV reactivation occurs with markedly increased frequency in patients with lymphoproliferative and immunodeficiency diseases, as well as transplant recipients receiving cyclosporin A (10), rapid methods of viral detection such as PCR may allow better monitoring of medications and early detection of EBV-related lymphomas that may arise in these patients.

Base Sequence↗
PubMed1989

Use of DNA amplification methods for clinical diagnosis in autoimmune diseases.

Autoimmune disease is generally felt to result from the interaction of genetic and environmental factors. In recent years, significant advances have been made in using recombinant DNA methods to analyze specific genetic factors and infectious agents. However, new techniques are needed that are more rapid, inexpensive, and suitable for small tissue biopsies obtained early in the course of disease. New methods of DNA amplification based on polymerase chain reaction (PCR) and Q beta-replicase (Q beta R) have recently been reported. These methods are briefly reviewed, and their potential applications to patients with autoimmune disease are presented. Several types of applications can be considered, including detection of: a) specific HLA-D alleles in order to predict prognosis and better utilize existing medications; b) bacterial, fungal, and spirochete infections in joint aspirates or synovial biopsies; c) human immunodeficiency virus (HIV) and other viruses (e.g., EBV, CMV) that may be associated with immune dysregulation in certain patients; and d) neoplastic transformation in blood or tissues by determining monoclonal gene rearrangements, karyotypic alterations or oncogene activation. It is likely that routine clinical laboratories will soon begin implementing DNA amplification methods in order to screen blood products for infectious agents (especially HIV and hepatitis B virus). Because these techniques will be readily available, rheumatologists/clinical immunologists should begin developing strategies that will allow them to use these methods in a cost-effective manner for diagnosis and monitoring treatment.

Autoimmune Diseases↗
PubMed1989

Studies of HIV infection and the development of Epstein-Barr virus-related B cell lymphomas following transfer of human lymphocytes to mice with severe combined immunodeficiency.

Mice with severe combined immunodeficiency (C.B-17 scid, hereafter SCID) accept xenografts of adult human peripheral blood leukocytes (PBL). The transplanted human PBL expand in number and survive for at least thirteen months and have been shown to reconstitute human immune function at both the T and B cell levels. Human immunoglobulin production is restored, and secondary antibody responses to antigens such as tetanus toxoid can be induced. All SCID mice reconstituted with 50 x 10(6) or more PBL from donors with evidence of exposure to Epstein-Barr virus (EBV) have developed human B cell lymphomas at 8-16 weeks after PBL engraftment, whereas mice reconstituted with PBL from EBV-seronegative donors fail to develop tumors. These tumors involve both lymphatic and non-lymphatic organs, and histologically they resemble large cell or immunoblastic lymphomas. The tumors are associated with high levels of human immunoglobulin secretion and serum electrophoresis reveals oligoclonal immunoglobulin banding patterns. Analysis of tumor DNA shows the presence of EBV genomes and oligoclonal patterns of immunoglobulin JH gene rearrangement. Taken together, these observations suggest an EBV-related proliferation of B lymphocytes leading to the rapid appearance of oligoclonal B cell malignancies following transfer of B lymphocytes from "normal" donors to SCID mice. SCID mice reconstituted with PBL from EBV-seronegative donors have been infected with the LAV-1 strain of human immunodeficiency virus (HIV-1). Virus has been recovered from most infected animals by co-culture of mouse tissue with human T lymphoblasts. Some mice with high virus titers have developed an acute wasting syndrome and depletion of human T cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Sjögren's syndrome nuclear antigen B (La): cDNA cloning, structural domains, and autoepitopes.

SS-B/La is a major antigenic target for autoantibodies in patients with Sjögren's syndrome. Its transient association with nascent RNA polymerase III transcripts in the cell nucleus suggest a functional role of SS-B/La in RNA processing and maturation. Human SS-B/La autoantibodies recognize at least two distinct epitopes on two separate structural domains of the SS-B/La protein and these epitopes are conserved among mammalian species. In contrast, murine monoclonal antibodies produced though immunization with purified bovine SS-B/La recognize different epitopes. To elucidate these differences, cDNA sequences of SS-B/La were cloned from several mammalian species including human, bovine, and rabbit. Complete human SS-B/La cDNAs including the coding sequence (1227bp) and untranslated sequences were isolated. The complete bovine sequence was determined from two overlapping partial cDNA clones. Comparison of the complete protein sequences encoded by the human and bovine cDNAs revealed a high degree of conservation of amino acid sequence showing only 26 substitutions/deletions out of 408 residues. RNA blot analysis indicated the presence of two size species of transcripts in bovine and rabbit cells, 1.8 kb and greater than 2.5 kb, in contrast to a single 1.8 kb mRNA species in human cells. The results of cDNA cloning support our previous finding of SS-B/La as a two-domain protein, and the RNA-binding site is confirmed to be located within N-terminal domain designated X. Epitope mapping using recombinant SS-B/La fusion proteins confirmed the findings of at least two autoepitopes located on different domains.

Animals↗
PubMed1989

Viral genomes in lymphomas of patients with Sjögren's syndrome.

The recent isolation of a new member of the herpes virus family (Human Herpes Virus-6, HHV-6) from patients with lymphoproliferative diseases prompted us to examine biopsies from six patients with primary Sjögren's Syndrome (SS) who developed non-Hodgkin's lymphoma. Five SS patients developed B-cell lymphoma and one developed a T-cell lymphoma based on immunoglobulin and T-cell antigen receptor (TCAR) gene rearrangements. In two SS patients with B-cell lymphomas, viral DNAs were detected, including: (a) Epstein-Barr Virus (EBV) DNA that exhibited an unusual pattern of restriction fragment length polymorphisms (RFLP) of the Bam M viral DNA segment; and (b) HHV-6 DNA in a second SS patient's lymphoma, with an RFLP similar to recent viral isolates from patients with other lymphoproliferative diseases. Viral DNA was not detected in the other four SS lymphoma biopsies. Also, all six biopsies were examined for presence of other viral DNAs (including CMV, HTLV, HIV and adenovirus) and were negative. Antibody titers to EBV-associated early-diffuse-antigen (EA-D), as assessed by ELISA method, and antibody titers against HHV-6, as detected by immunofluorescence and radio-immunoprecipitation assays, were markedly elevated in several SS patients with lymphoma and pseudolymphoma. These results suggest a potential role of EBV or HHV-6 in the neoplastic transformation that occurs with increased frequency in SS patients.

Antigens, Viral↗
PubMed1988

Human T-lymphocyte activation is associated with changes in O-glycan biosynthesis.

The activation of human T-lymphocytes by anti-CD3 antibodies and interleukin-2 results in a marked increase in apparent molecular weight of the major cell-surface sialoglycoprotein. Both forms of the sialoglycoprotein were identified as leukosialin by a monospecific antiserum, and the differences in molecular weight were found to be due to changes in the carbohydrate structures. Our results suggest that resting T-lymphocytes express on leukosialin the disialotetrasaccharides NeuNAc alpha 2----3Gal beta 1----3(NeuNAc alpha 2----6)Gal-NAc-Ser/Thr, whereas activated human T-cells carry on leukosialin exclusively the more complex structures NeuNAc alpha 2----3Gal beta 1----3(NeuNAc alpha 2----3Gal beta 1----4GlcNAc beta 1----6)GalNAc-Ser/Thr. The radical shift in the biosynthetic pathway of O-glycans in activated T-lymphocytes compared to resting cells is apparently caused by a decrease of alpha 2----6 sialyltransferase activity and by the parallel dramatic stimulation of the beta 1----6GlcNAc-transferase. Since both enzymes compete for the same precursor substrate, the coordinate changes in their activities are most likely responsible for the complete change of the carbohydrate structures on leukosialin during the activation of human T-lymphocytes.

Antigens, CD↗
PubMed1988

Treatment of primary Sjögren's syndrome with hydroxychloroquine.

Sjögren's syndrome is an autoimmune disease characterized by lymphocytic infiltration of the salivary/lacrimal glands, autoantibody production, and polyclonal hyperglobulinemia. In view of the efficacy and relative safety of hydroxychloroquine in other autoimmune disorders, the potential benefit of hydroxychloroquine (200 mg per day for 12 months) in 10 patients with Sjögren's syndrome was evaluated. Changes in levels of total immunoglobulin, antibody against Sjögren's syndrome-associated antigen B, rheumatoid factor, and in vitro production of immunoglobulin in the serum were evaluated. For comparison, 10 patients matched according to age and sex, who did not receive hydroxychloroquine were studied. In the hydroxychloroquine-treated group, the following observations were made: (1) significantly decreased total immunoglobulin G (IgG) and IgA levels with little change in IgM levels; (2) significant decrease in IgA-rheumatoid factor with a smaller decrease in IgM-rheumatoid factor; (3) decreased IgG anti-Sjögren's syndrome-associated antigen B autoantibody; and (4) decreased erythrocyte sedimentation rate and increased hemoglobin level. Further, a specific idiotype present on their rheumatoid factor (defined by monoclonal antibody 17-109) was significantly decreased, with disappearance of detectable circulating paraprotein in two hydroxychloroquine-treated patients. Finally, rheumatoid factor production in vitro by lymphocytes from hydroxychloroquine-treated patients using a T cell-dependent mitogen was significantly decreased. These results suggest that hydroxychloroquine modulates lymphoproliferation in patients with Sjögren's syndrome and may prevent progression to extraglandular sites of neoplastic transformation.

Autoantibodies↗
PubMed1987

Molecular basis for the cross-reactive idiotypes on human anti-IgG autoantibodies (rheumatoid factors).

High titres of anti-IgG autoantibodies (rheumatoid factors, RF) are characteristic of patients with rheumatoid arthritis, Sjögren's syndrome, and mixed cryoglobulinaemia, and may contribute to immune complex formation and tissue damage. The monoclonal RFs from cryoglobulinaemia patients frequently display cross-reactive idiotypes. The genetic basis for the cross-reactive idiotypes on RF autoantibodies has not been determined. To clarify structural and genetic relationships among RFs from unrelated subjects, a series of anti-peptide antibodies have been generated that define primary sequence-dependent idiotypes on RF heavy and light chains. Multiple monoclonal and polyclonal RFs from unrelated individuals have been probed by Western blotting with the anti-idiotypic reagents. The results show that sequences in the kappa light chain variable region represent a common structural element among RF autoantibodies. This hypothesis is confirmed by the cloning and sequencing of the conserved germline variable region gene which encodes human RF kappa chains.

Antibody Specificity↗
PubMed1987

Rheumatoid factor and immune networks.

Rheumatoid factors represent a normal component of the immune network. The autoantibodies promote complement fixation and clearance of immune complexes. They amplify the avidity of polyclonally induced IgG. Genes related to the primary structure of rheumatoid-factor light chains are widely distributed in the human population and have been conserved during the evolution and dispersion of the species. Products of these genes may be detected with anti-idiotypic antibodies against synthetic peptides corresponding to individual hypervariable regions on rheumatoid-factor light chains. Such anti-peptide antibodies provide unique reagents for analyzing the genetics of immunoglobulins in outbred populations. Precursors of rheumatoid factor are abundant among immature B lymphocytes. Some of these cells may tend to localize to mucosal surfaces, where they are stimulated directly by pathogenic microorganisms with polyclonal B cell-activating properties. Synthesis of rheumatoid factor regularly accompanies all secondary immune responses but is usually transient. Production of the autoantibody is T-cell dependent. The T cells may recognize antigen in an IgG-antigen immune complex that is processed and presented by B-cell precursors of rheumatoid factor. Rheumatoid factor-associated light-chain idiotypes are rare in serum IgG and on IgG myeloma proteins. They are common among monoclonal IgM proteins and on the surface of the malignant B cells from patients with chronic lymphatic leukemia. The rheumatoid factors that are produced by patients with mixed cryoglobulinemia, or primary Sjogren's syndrome can share idiotypic antigens with monoclonal rheumatoid factors. Rheumatoid factor synthesis in the diseases may reflect an abnormal proliferation of B-cells that is not antigen-driven and that can degenerate into malignancy. The rheumatoid factors in patients with rheumatoid arthritis are diverse and almost certainly represent the outcome of antigen-induced, T cell-dependent mechanisms. The antigens that drive the T cells have not been identified but could represent exogenous microorganisms, self components, or idiotypic antigens that fortuitously interact with rheumatoid factors.

Autoantibodies↗
PubMed1987

Potential role of Epstein-Barr virus in Sjögren's syndrome.

Sjögren's syndrome is an autoimmune disease characterized by lymphocytic infiltration and destruction of salivary and lacrimal glands. This condition may occur as a primary condition or may be associated with other autoimmune disorders such as rheumatoid arthritis or systemic lupus. Because the environmental factors that initiate SS are unknown, we have investigated the potential role of EBV, CMV, and other viruses. We observed that epithelial cells in salivary gland biopsies of patients with SS contained antigens reactive with monoclonal antibodies against EBV-associated antigens. These antigens were not found in other tissues of patients with SS and were not detectable in salivary gland biopsies from normal persons and patients with other autoimmune diseases lacking SS. The molecular weight of the antigens present in the SS salivary gland extracts was similar to that expressed in cells containing reactivated EBV. Also, the content of EBV DNA in the saliva of patients with SS was significantly greater than in age-, sex-matched controls or persons with other autoimmune disorders. These studies provide one of the first examples where a specific viral agent may be implicated in perpetuating a chronic autoimmune disease. These results also may provide insight into other autoimmune diseases where the target organ is less accessible to biopsy.

Antigens, Viral↗
PubMed1986

Detection of Epstein-Barr virus-associated antigens and DNA in salivary gland biopsies from patients with Sjogren's syndrome.

Sjogren's syndrome (SS) is an autoimmune disorder characterized by lymphocytic infiltration of salivary and lacrimal glands. To determine whether Epstein-Barr virus (EBV) might play a role in the pathogenesis of this disorder, we used monoclonal antibodies and DNA probes to detect evidence of viral gene products and genomes in these patients' tissue biopsies and saliva. Cytoplasmic staining of epithelial cells (i.e., ductal and/or acinar cells) with monoclonal antibody against the EBV-encoded early antigen (EA-D) was noted in 8/14 salivary gland biopsies from SS patients. This antibody did not react with normal salivary glands or salivary gland tumors, nor with other tissues from SS patients. The reactive antigen in SS biopsies had a m.w. of 52,000 on the basis of immunoblotting experiments, similar to the EA-D antigen found in lymphoblastoid cells lytically infected with EBV. EBV DNA was detected in parotid biopsies from two SS patients in amounts ranging from 0.1 to 3 pg per 20 micrograms of cellular DNA. Southern blotting was used to demonstrate the reactivity with Bam V, Eco D, and Bam M probes. Parotid saliva samples from 8/20 SS patients contained EBV DNA detectable by slot blot hybridization. EBV DNA was not detected in saliva of age-matched controls, rheumatoid arthritis patients lacking sicca symptoms, or patients with benign parotid tumors. The presence of EBV in salivary gland and saliva samples was associated with clinically more severe SS, as manifested by extraglandular symptoms such as vasculitis, occurrence of "pseudolymphoma", and marked abnormalities in immunoglobulin levels. These results demonstrate an elevated content of EBV in salivary glands of SS patients, and suggest that this virus may play a role in pathogenesis.

Antibodies, Monoclonal↗
PubMed1986

A distinct endothelial cell recognition system that controls lymphocyte traffic into inflamed synovium.

Lymphocytes are essential mediators of normal tissue inflammatory reactions and of pathologic tissue damage in, for example, rheumatoid arthritis and other autoimmune diseases. In a study of the mechanisms controlling lymphocyte entry into sites of inflammation from the blood, the function and specificity of lymphocyte-endothelial interactions were examined in inflamed joint tissue (synovium) from patients with rheumatoid arthritis. Synovial high endothelial venules (HEV) supported the binding of normal peripheral blood lymphocytes in vitro. The characteristics of this binding, which were similar to those of lymphocyte-HEV interactions controlling lymphocyte migration into organized lymphoid tissues, included a requirement for calcium ions, a dependence on metabolic activity, and a preferential adherence of circulating lymphocytes as opposed to immature thymocytes. However, the binding of lymphocytes to synovial HEV was not inhibited by a monoclonal antibody to lymphocyte receptors for lymph node HEV, and synovial HEV failed to bind either lymph node HEV-specific or mucosal HEV-specific B lymphoblastoid cells. The results suggest that a lymphocyte-endothelial cell recognition system that is distinct from such systems in organized lymphoid tissues directs the extravasation of normal lymphocytes as well as pathologically important effector cells into inflamed synovium.

Animals↗