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At least 343 records · Page 19Linked to original sources
PubMed1991

Effector mechanisms in organ-specific autoimmunity. I. Characterization of a CD8+ T cell line that mediates murine interstitial nephritis.

To further investigate mechanisms of cell-mediated tissue destruction in an organ-specific autoimmune disease, we have established and characterized a nephritogenic CD8+ T cell line. This target antigen-specific effector T cell line, M52, was derived from bulk populations of CD8+ T cells isolated from susceptible animals immunized to produce anti-tubular basement membrane (alpha TBM) disease. Our studies show that M52 retains the phenotypic and functional characteristics of nephritogenic T cells induced in vivo. M52 mediates antigen-specific delayed-type hypersensitivity (DTH) responses to the target antigen 3M-1, it is cytotoxic to 3M-1-expressing renal tubular epithelial cells in vitro, and it adoptively transfers interstitial nephritis to naive syngeneic recipients. Clonal analysis of these nephritogenic CD8+ T cells reveals distinct functional phenotypes within the M52 cell line. We have isolated a cytotoxic CD8+ clone, M52.26, which is not DTH-reactive to 3M-1, and multiple DTH-reactive clones which mediate less efficient cytotoxicity to 3M-1-expressing target cells. Cytofluorographic analysis of four randomly selected clones reveals alpha beta T cell receptor expression. Further characterization of these functionally distinct CD8+ T cell clones will help to define their respective roles in mediating tubular epithelial cell injury and the inflammatory lesion of autoimmune interstitial nephritis.

Amino Acid Sequence↗
PubMed1990

A species and organ specific glomerular basement membrane antigen.

By the use of a monoclonal antibody reacting with the human glomerular basement membrane exclusively we have been isolating a specific glomerular antigen. The antibody failed to react with other renal structures and other basement membranes and extracellular matrix constituents of other organs or plasma proteins. It did not react with glomerular basement membranes of other species as mice and rats. For the isolation of the antigen we applied affinity chromatography, on Sepharose beads coupled to the monoclonal antibody PM II 34 G3. From this column the antigen was eluted under acid conditions. In 8% polyacrylamide gel electrophoresis the approximate molecular weight was estimated with 14400 daltons, which was confirmed on high pressure liquid chromatography using the Bio-Sil TSK method. The antigen was temperature sensitive in that at high temperatures (60 degrees C) several bands on SDS-PAGE and several peaks on HPLC could be noted. This could be responsible for the crystal formation after treatment/concentration on the rotary vacuum pump at 60 degrees C. Preliminary data of amino acid analysis showed a high glycine content pointing towards a collageneous molecule. But cross reactivity with many connective tissue proteins could be ruled out by immuno-histochemical techniques and affinity chromatography. A major point of interest is that this antigen can be detected in human urine under physiological conditions. We are herewith reporting the first species and organ specific glomerular basement membrane antigen.

Amino Acids↗
PubMed2002

Organ-specific CD4+ T cell response during Listeria monocytogenes infection.

The immune response against the intracellular bacterium Listeria monocytogenes involves both CD4(+) and CD8(+) T cells. We used the MHC class II-presented peptide listeriolysin(189-201) to characterize the organ-specific CD4(+) T cell response during infection. Systemic listeriosis resulted in a strong peptide-specific CD4(+) T cell response with frequencies of 1/100 and 1/30 CD4(+) splenocytes at the peak of primary and secondary response, respectively. This response was not restricted to lymphoid organs, because we detected specific CD4(+) T cells in all tissues analyzed. However, the tissue distribution of the T cell response was dependent on the route of infection. After i.v. infection, the strongest CD4(+) T cell response and the highest levels of memory cells were observed in spleen and liver, the major sites of L. monocytogenes replication. After oral infection, we detected a strong response in the liver, the lamina propria, and the intestinal epithelium. These tissues also harbored the highest frequencies of listeriolysin(189-201)-specific CD4(+) memory T cells 5-8 wk post oral infection. Our results show that kinetics and magnitude of the CD4(+) T cell response and the accumulation of CD4(+) memory T cells depend on the route of infection and are regulated in a tissue-specific way.

Administration, Oral↗
PubMed1991

Organ-specific modification of tumor development by low-dose combinations of agents in a rat wide-spectrum carcinogenesis model.

The combined effects of low doses of various carcinogens and carcinogenesis modifiers on tumor development were investigated by using a wide-spectrum organ carcinogenesis model in F344 rats. These agents were administered as three groups: (1) a group of known hepatocarcinogens; (2) a group of nitroso compounds having various target organ specificities; and (3) a group of antioxidants having various inhibiting or enhancing activities depending on the target organ. Doses were used which were generally below the known effective level for the individual chemical. These groups of chemicals were administered with or without prior administration of N-diethylnitrosamine (100 mg/kg body wt., i.p.), N-methylnitrosourea (4 x 20 mg/kg body wt., i.p.) and dihydroxy-di-N-propylnitrosamine (0.1% in drinking water for 2 weeks). The hepatocarcinogen group in combination with various nitroso compounds increased the incidences of liver hyperplastic nodules and hepatocellular carcinomas. In contrast, incidences were clearly reduced when the hepatocarcinogens and/or the nitroso compounds were administered in combination with the antioxidants. For the urinary bladder, the combination with nitroso compounds and antioxidants enhanced cancer development, and the addition of hepatocarcinogens further increased tumorigenesis. For the glandular stomach, additive effects on the numbers of pepsinogen isozyme 1-altered pyloric glands, a putative preneoplastic lesion, were produced by the combination treatment of antioxidants and the nitroso compounds. No synergistic effects on tumor development were seen in other organs. The results of the present study demonstrated that combinations of various compounds at low doses can additively or synergistically exert either enhancing or inhibitory effects on the development of preneoplastic and neoplastic lesions in different organs in a single model having a wide spectrum of organ effects.

Animals↗
PubMed1991

Organ-specific patterns of gene expression in the reproductive tract of Drosophila are regulated by the sex-determination genes.

The sex-determination genes of Drosophila act to repress the developmental pathway for the internal somatic reproductive organs of the opposite sex. By misregulating this pathway during preadult development, the organ-specific expression pattern of the glucose dehydrogenase gene (Gld) in the reproductive tract of adult flies has been changed without a concomitant sexual transformation of the reproductive organs. Misregulation of the tra, tra-2, and dsx genes leads to very similar patterns of ectopic expression of Gld. The induced ectopic patterns of Gld expression at the adult stage occur in a small subset of organs which all normally express the Gld gene during their morphogenesis. These ectopic patterns are irrevocably set during late larval-early pupal development. The normal pattern of Gld expression in several other Drosophila species is quite similar to the ectopic patterns which we have generated in D. melanogaster, suggesting that the interspecific variation in Gld expression may result from variation in the expression of the sex-determination genes.

Animals↗
PubMed1983

Genetic control of the organ specificity of lymphoproliferative disease virus (LPDV) of turkeys.

In a previous study based on the kinetics of virus replication and tumor formation (Gazit et al., 1982), it was shown that the organotropism of lymphoproliferative disease virus (LPDV) is confined to lymphoid tissues. The present paper demonstrates that this organ specificity is controlled at the level of infection and integration, that is, the lymphoid organs, which are the only organs sustaining virus replication, and also the only organs in whose cells integrated LPDV proviruses are detectable. At the same time, the efficiency of virus replication within the various target organs is regulated both at the level of infection and integration and at the level of viral gene transcription.

Animals↗
PubMed1994

Oral tolerance: immunologic mechanisms and treatment of animal and human organ-specific autoimmune diseases by oral administration of autoantigens.

Oral tolerance is a long recognized method to induce peripheral immune tolerance. The primary mechanisms by which orally administered antigen induces tolerance are via the generation of active suppression or clonal anergy. Low doses of orally administered antigen favor active suppression whereas higher doses favor clonal anergy. The regulatory cells that mediate active suppression act via the secretion of suppressive cytokines such as TGF beta and IL-4 after being triggered by the oral tolerogen. Furthermore, antigen that stimulates the gut-associated lymphoid tissue preferentially generates a Th2 type response. Because the regulatory cells generated following oral tolerization are triggered in an antigen-specific fashion but suppress in an antigen nonspecific fashion, they mediate "bystander suppression" when they encounter the fed autoantigen at the target organ. Thus it may not be necessary to identify the target autoantigen to suppress an organ-specific autoimmune disease via oral tolerance; it is necessary only to administer orally a protein capable of inducing regulatory cells that secrete suppressive cytokines. Orally administered autoantigens suppress several experimental autoimmune models in a disease- and antigen-specific fashion; the diseases include experimental autoimmune encephalomyelitis (EAE), uveitis, and myasthenia, collagen- and adjuvant-induced arthritis, and diabetes in the NOD mouse. In addition, orally administered alloantigen suppresses alloreactivity and prolongs graft survival. Initial clinical trials of oral tolerance in multiple sclerosis, rheumatoid arthritis, and uveitis have demonstrated positive clinical effects with no apparent toxicity and decreases in T cell autoreactivity.

Administration, Oral↗
PubMed2000

Early tumor growth in metastatic organs influenced by the microenvironment is an important factor which provides organ specificity of colon cancer metastasis.

We have previously demonstrated that liver metastases in nude mice and lung metastases in nude rats occurred specifically, when KM12SM human colon carcinoma cells were inoculated orthotopically into the cecal wall of nude mice and rats. To clarify the relationship between the tumor growth potential in the metastatic organs and the metastatic organ preference in these two metastatic models, we have evaluated the in vitro cell growth activities affected by the organ conditioned medium (CM) from the liver and lung, and the in vivo growth activities of the ectopic implanted tumors in the liver and lung. The tumorigenicity of the ectopic implanted tumors was 100% in mouse liver, 33% in rat liver, 50% in mouse lung, and 75% in rat lung. The crude liver CM of the animals showed inhibitory activities for KM12SM cell growth in a dosage-dependent manner, and the crude lung CM stimulated KM12SM cell growth. The liver CM of nude mice inhibited the KM12SM cell growth more strongly compared with the CM of nude rats, and the lung CM of nude rats was more strongly stimulated compared with the CM of nude mice. The liver CM of nude mice had non-heparin binding factors, which stimulated or inhibited KM12SM cell growth, in a molecular weight range of 50 to 100 kDa. By contrast, the liver CM of nude rats showed no growth stimulating activity for KM12SM cells. These results suggest that the metastatic organ specificity of KM12SM cells may depend on the early tumor growth influenced by the microenvironment in metastatic organs.

Animals↗
PubMedDate not supplied

Clinical characteristics and etiological markers in insulin-dependent diabetes associated with an organ-specific autoimmune disease.

Thirty-four insulin-dependent diabetics with a coexistent organ-specific autoimmune disease (Graves' disease, primary myxedema, adrenal insufficiency, generalized vitiligo, primary biliary cirrhosis) were compared to 100 insulin-dependent patients in whom no obvious etiology was detectable. The autoimmune group was characterized by a predominance of females, a family history of autoimmune disease, a later age at onset, better glycemic control, low insulin requirement, persistence of ICA, and greater frequency of HLA B8 but not of B18. However, there was a large overlap between the two groups for all these criteria. In addition, a family history of IDD in first degree relatives and the frequency of serum positive for neutralizing anti-Coxsackie B antibodies were identical in the two groups. These results do not justify the separation of this group of patients as having purely autoimmune diabetes, to the exclusion of other etiological factors, whether genetic or viral.

Adult↗
PubMed1991

Organ-specific invertase deficiency in the primary root of an inbred maize line.

An organ-specific invertase deficiency affecting only the primary root system is described in the Oh 43 inbred maize (Zea mays). Invertases (acid and neutral/soluble and insoluble) were assayed in various tissues of hybrid (NK 508) and inbred (Oh 43, W 22) maize lines to determine the basis for an early report that Oh 43 root tips were unable to grow on sucrose agar (27). Substantial acid invertase activity (7.3 to 16.1 micromoles of glucose per milligram of protein per hour) was evident in extracts of all tissues tested except the primary root system of Oh 43. This deficiency was also evident in lateral roots arising from the primary root. In contrast, morphologically identical lateral roots from the adventitious root system had normal invertase levels. These results suggest that ontogenetic origin of root tissues is an important determinant of invertase expression in maize. Adventitious roots (including the seminals) arise above the scutellar node and are, therefore, of shoot origin. The Oh 43 deficiency also demonstrated that invertase activity was not essential for maize root growth. Sucrose synthase was active in extracts from all root apices and theoretically provided the only available avenue for sucrose degradation in primary root tips of Oh 43. The deficiency described here will provide a useful avenue of investigation into the expression and significance of root invertase.

Journal Article↗
PubMed1984

Demonstration of organ specific antibodies against heart mitochondria (anti-M7) in sera from patients with some forms of heart diseases.

Using submitochondrial particles (SMP) from beef heart, pig kidney and rat liver in the ELISA, we detected partial organ specific anti-mitochondrial antibodies (AMA) against heart and kidney SMP in sera from patients with different forms of cardiomyopathies. Serum samples from 50 of 159 patients with congestive or hypertrophic cardiomyopathy (31%) and from two of 15 patients with acute myocarditis (13%) were AMA positive. These AMA could be clearly differentiated from other known AMA (anti-M1-M6) and were therefore named anti-M7. Thirteen of the 52 sera (25%) reacted only with heart SMP (type a) and 39 showed a cross-reaction with kidney, lung and pancreas mitochondria (type b). However, using liver SMP, no positive reaction was found. The anti-M7 type a and b activity was abolished completely by absorption with heart SMP. The anti-M7 antibodies were directed against an antigen which co-purified with the inner mitochondrial membrane and had a molecular weight of 67,000-72,000. They seem to be confined to some forms of cardiomyopathies and myocarditis of unknown aetiology and were not detected in sera from patients with other diseases.

Animals↗
PubMed1995

The role of IL-12 in the induction of organ-specific autoimmune diseases.

The concept that T cells are subdivided into T helper 1 (Th1) and Th2 subsets was recently extended to suggest that Th1 cells contribute to the pathogenesis of several organ-specific autoimmune diseases, whereas Th2 cells inhibit disease development. Here, Sylvie Trembleau and colleagues examine the role of interleukin 12 (IL-12), a key cytokine guiding the development of Th1 cells, in the induction of autoimmune diseases, and discuss potential immunointervention strategies based on administration of IL-12 antagonists.

Animals↗
PubMed2001

Control of organ-specific autoimmunity by immunoregulatory CD4(+)CD25(+) T cells.

CD4(+)CD25(+) T cells regulate the activity of autoreactive T cells. Depletion of these cells results in the development of a wide-spectrum of organ-specific autoimmune diseases. In vitro model systems have been developed to study the function of these potent suppressor cells. Following their activation via their T-cell receptor, they downregulate the responses of CD25(-) effectors by a T-T interaction.

Animals↗
PubMed1995

Myasthenia gravis, a model of organ-specific autoimmune disease.

Myasthenia gravis (MG) is a neuromuscular disorder of autoimmune origin. Most patients have antibodies directed against the acetylcholine receptor (AChR) that interfere with neuromuscular transmission. MG is a model of organ-specific autoimmune disease in which the autoantigen, AChR, is well characterized. However, several questions remain unanswered. Why is AChR, which is present in the thymus, not tolerized? Why does the anti-AChR antibody titre not correlate with clinical manifestations, and why do some patients not have such antibodies? What genetic elements are involved in disease susceptibility? How is the expression of AChR regulated after its attack by autoantibodies? Could MG patients benefit from new immunomodulatory treatments? At the IVth EuroMyasthenia meeting, held in Versailles in April 1994, almost 200 researchers and physicians met to discuss the pathophysiology and treatment of myasthenia gravis and to provide answers to some of these questions. The sessions covered immunological, genetic and clinical aspects of MG.

Autoantibodies↗
PubMed2006

Organ specific apoptosis following polymicrobial intraperitoneal infection.

BACKGROUND: Leukocyte apoptosis allows safe removal of potentially harmful cells and facilitates resolution of inflammation. We hypothesized that the number of apoptotic cells changes in a disproportionate fashion in parenchymal organs in response to intra-abdominal infection. MATERIALS AND METHODS: The percentage of apoptotic cells in the liver, spleen, lung, and peripheral blood was evaluated following cecal ligation and puncture (CLP) in mice. Tissue myeloperoxidase (MPO) levels were measured as an index of neutrophil extravasation. RESULTS: Liver & spleen MPO continually increased, while lung MPO remained low after CLP. In parallel to the increase in MPO, liver & spleen apoptosis continually increased throughout the 9-day follow-up period, whereas lung apoptosis remained unchanged. CONCLUSIONS: The distribution of apoptotic cells during intraperitoneal infection occurs in an organ specific manner, with significant increases in the spleen and liver. This distribution likely reflected the clearance of apoptotic cells as the inflammatory focus became contained.

Abdominal Abscess↗
PubMed1971

L-tryptophan. A non-allosteric organ-specific uncompetitive inhibitor of human placental alkaline phosphatase.

l-Tryptophan, but not d-tryptophan, inhibits human placental and intestinal alkaline phosphatases, but not those of liver and bone. The nature of this stereospecific organ-specific inhibition has been elucidated. Thus, from a study of the effect of substrate concentration on inhibition in which double-reciprocal plots of 1/v versus 1/s at various inhibitor concentrations were made, this inhibition is judged to be ;uncompetitive'. That the inhibition is non-allosteric is an opinion based on (1) hyperbolic curves obtained from plotting the percentage inhibition against inhibitor concentration; (2) the independence of the inhibition to heat denaturation and urea treatment; (3) the relatively low value of entropy change; and (4) a value close to unity for n, the number of l-tryptophan molecules that combine with one molecule of enzyme. Finally, a homosteric mechanism is further postulated for the inhibition by l-tryptophan based on the increase of optimum temperature for maximum velocity and the decrease of this inhibition with increasing temperature. The mechanism of this inhibition is discussed.

Alkaline Phosphatase↗
PubMed1989

[Aspects of organ-specific autoimmunity in cluster headache].

Fourty-eight cluster headache patients have been studied. Twenty-nine of them were affected also by rhythm cardiac abnormalities, and the other 19 by associated conjunctival hyperaemia. The presence of organ-specific autoantibodies was investigated by immunofluorescence. High titers of antibodies against cardiac antigenic determinants was found. The study of leukocyte subpopulations revealed a parallel increase in blood and in conjunctival mucosa of Leu7+ and LeuM3+ cells. These outcomes confirm the immunopathological theory of cluster headache.

Autoantibodies↗