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Biomedical subjects

J S Moore

Publications and source records attributed to J S Moore.

At least 73 records · Page 4Linked to original sources

Transforming growth factor-beta inhibits human T-cell proliferation through multiple targets.

This study investigates further the inhibitory effects of transforming growth factor-beta (TGF-beta) on human T-lymphocyte responses to mitogenic stimulation. T cells were stimulated either with mitogenic concentrations of PHA or with submitogenic concentrations of Con A followed by the addition of IL-2. DNA synthesis ([3H]thymidine incorporation) in both systems was inhibited by 60-69% in the presence of TGF-beta, with maximal reduction occurring on days 4 and 5 of culture. Cell surface expression of transferrin receptor (TfR) and IL-2 receptor-alpha (p55) were inhibited by 20-80% in the Con A/rIL-2 system and 20-45% in the PHA system in the presence of TGF-beta. In addition, mitogen-induced up-regulation of TfR and IL-2R mRNA levels were inhibited by TGF-beta. Finally, we investigated the effect of TGF-beta on the assembly of clathrin monomers into assembled coated pits and vesicles, and essential step in TfR and IL-2R alpha turnover. Stimulation of T cells using either mitogen system resulted in an increase in the level of assembled clathrin, which was almost completely inhibited by TGF-beta. These findings suggest that TGF-beta may act at several sites in mitogen-mediated proliferative pathways to contribute to the inhibition of T-cell proliferation.

Clathrin↗

Expression of human glycophorin A in wild type and glycosylation-deficient Chinese hamster ovary cells. Role of N- and O-linked glycosylation in cell surface expression.

Glycophorin A, the most abundant sialoglycoprotein on human red blood cells, carries several medically important blood group antigens. To study the role of glycosylation in surface expression and antigenicity of this highly glycosylated protein (1 N-linked and 15 O-linked oligosaccharides), glycophorin A cDNA (M-allele) was expressed in Chinese hamster ovary (CHO) cells. Both wild type CHO cells and mutant CHO cells with well defined glycosylation defects were used. Glycophorin A was well expressed on the surface of transfected wild type CHO cells. On immunoblots, the CHO cells expressed monomer (approximately 38 kDa) and dimer forms of glycophorin A which co-migrated with human red blood cell glycophorin A. The transfected cells specifically expressed the M blood group antigen when tested with mouse monoclonal antibodies. Tunicamycin treatment of these CHO cells did not block surface expression of glycophorin A, indicating that, in the presence of normal O-linked glycosylation, the N-linked oligosaccharide is not required for surface expression. To study O-linked glycosylation, glycophorin A cDNA was transfected into the Lec 2, Lec 8, and ldlD glycosylation-deficient CHO cell lines. Glycophorin A with truncated O-linked oligosaccharides was well expressed on the surface of ldlD cells (cultured in the presence of N-acetylgalactosamine alone), Lec 2 cells, and Lec 8 cells with monomers of approximately 25 kDa, approximately 33 kDa, and approximately 25 kDa, respectively. In contrast, non-O-glycosylated glycophorin A (approximately 19-kDa monomers) was poorly expressed on the surface of ldlD cells cultured in the absence of both galactose and N-acetylgalactosamine. Thus, under these conditions, in the absence of O-linked glycosylation, the N-linked oligosaccharide itself is not able to support appropriate surface expression of glycophorin A in transfected CHO cells.

Animals↗

Variable region gene analysis of pathologic human autoantibodies to the related i and I red blood cell antigens.

To investigate the molecular basis of the autoimmune response to the related i and I carbohydrate antigens, we studied cold agglutinins (CA) from B-cell clones and from the peripheral circulation of patients with lymphoproliferative syndromes. Sequence analyses of expressed variable region genes indicate that both anti-i and anti-I specificities from B-cell clones from two patients are encoded by the VH4.21 or a very closely related VH4 heavy chain gene, whereas the expressed light chain genes differed. The anti-i-secreting B-cells express unmutated germline-encoded VH4.21 and VKI gene sequences. The VH region gene encoding anti-I has the closest homology (97%) to the VH4.21 germline gene and differs at the protein level by only three amino acids. In contrast, while the VL region gene encoding anti-I is most homologous (96%) to the VKIII, kv328 germline gene, there are seven amino acid differences due to nonrandom replacement mutations, which suggests a role for antigen-mediated selection in the anti-I response of this individual. These studies were extended by a structural survey of 20 additional serum CA using antipeptide antibodies specific for determinants in VH and VL regions. All anti-I and anti-i CA were shown to express VH4 heavy chains, and 14 of 17 CA expressed a previously described VH4 second hypervariable region determinant, termed VH4-HV2a. We also found that 13 of 14 anti-I CA used VKIII light chains, while the anti-i CA used light chains from at least three VL families. Taken together, the data show that anti-i and anti-I CA probably both derive from the VH4.21 gene (or a closely related gene). Furthermore, the restricted VH and different VL gene use in anti-i and anti-I CA may reflect the close structural relationship of the i and I antigens.

Autoantibodies↗

Aphid derived sugars in the neotropical sandfly--Lutzomyia peruensis.

It is known that a sugar meal is a prerequisite for the transmission of Leishmania by sandflies in the laboratory. Lutzomyia peruensis the proven vector of Leishmania peruviana, was caught by aspiration from crevices in rocks near Chaute in the Rimac Valley, Peru, cryopreserved and analysed for sugars using HPLC. The major sugars present are glucose and fructose as well as smaller amounts of sucrose, maltose, melibiose, turanose and a trisaccharide, probably raffinose. The results indicate that the major carbohydrate sugar meal of Lutzomyia peruensis is aphid honeydew. This is the first report of such behaviour in Neotropical sandflies.

Animals↗

Use of blood and blood products.

It is sometimes necessary for the practitioner to transfuse the ruminant with whole blood or plasma. These techniques are often difficult to perform in practice and are time-consuming, expensive, and stressful to the animal. Acute loss of 20-25% of the blood volume will result in marked clinical signs of anemia, including tachycardia and maniacal behavior. The PCV is only a useful tool with which to monitor acute blood loss after intravascular equilibration with other fluid compartments has occurred. An acutely developing PCV of 15% or less may require transfusion. Chronic anemia with PCV of 7-12% can be tolerated without transfusion if the animal is not stressed and no further decline in erythrocyte mass occurs. Seventy-five per cent of transfused bovine erythrocytes are destroyed within 48 hours of transfusion. A transfusion rate of 10-20 ml/kg, recipient weight, is necessary to result in any appreciable increase in PCV. A nonpregnant donor can contribute 10-15 ml of blood/kg body weight at 2-4 week intervals. Sodium citrate is an effective anticoagulant, but acid citrate dextrose should be used if blood is to be stored for more than a few hours. Blood should not be stored more than 2 weeks prior to administration. Heparin is an unsuitable anticoagulant because the quantity of heparin required for clot-free blood collection will lead to coagulation defects in the recipient. Blood crossmatching is only rarely performed in the ruminant. In field situations, it is advisable to inject 200 ml of donor blood into the adult recipient and wait 10 minutes. If no reaction occurs, the rest of the blood can probably be safely administered as long as volume overload problems do not develop. Adverse reactions are most commonly seen in very young animals or pregnant cattle. Signs of blood or plasma transfusion reaction include hiccoughing, tachycardia, tachypnea, sweating, muscle tremors, pruritus, salivation, cough, dyspnea, fever, lacrimation, hematuria, hemoglobinuria, collapse, apnea, and opisthotonos. Intravenous epinephrine HCl 1:1000 can be administered (0.2 to 0.5 ml) intravenously or (4 to 5 ml) intramuscularly if clinical signs are severe. Pretreatment with antipyretics and slowing the administration rate may decrease the febrile response. Blood or plasma administered too rapidly will also result in signs of cardiovascular overload, acute heart failure, and pulmonary hypertension and edema. Furosemide and slower administration of blood or plasma should alleviate this problem.(ABSTRACT TRUNCATED AT 400 WORDS)

Anemia↗

Increased assembly of clathrin occurs in response to mitogenic activation of murine lymphocytes.

The unassembled (soluble) and assembled (particulate) pools of clathrin in murine lymphocytes have been separated by centrifugation, and specifically quantified by immunoblotting of cellular extracts with an anticlathrin heavy chain monoclonal antibody. In resting spleen lymphocytes only 25-30% of the total cellular clathrin was found to be present in an assembled form. Upon activation of lymphocytes with B or T cell mitogens (lipopolysaccharide or concanavalin A), the levels of assembled clathrin increased to 60% of the total. These changes in the levels of assembled clathrin were not due to an increase in total cellular clathrin concentration following lymphocyte activation, but rather to changes in the steady state ratio of assembled to unassembled clathrin. The increase in assembled clathrin preceded the expression of transferrin receptors, as measured by the cell surface binding of an antitransferrin receptor monoclonal antibody, and maximal DNA synthesis, indicating that clathrin assembly occurs early after lymphocyte activation and precedes cell division. Immunofluorescence analysis of activated lymphocytes with an anti-clathrin heavy chain monoclonal antibody revealed a punctuate staining pattern characteristic of coated pits and vesicles. Activated B lymphocytes displayed particularly prominent staining in the perinuclear region compared to T cells, suggesting that clathrin assembly may be important for B cell functions such as immunoglobulin synthesis or secretion. These results suggest that in lymphocytes, clathrin assembly is a dynamic process that is triggered by mitogenic stimuli.

Animals↗

Defective isotype-specific regulation of IgA anti-erythrocyte autoantibody-forming cells in NZB mice.

B cell hyperactivity characterizes many autoimmune diseases. In NZB mice this is manifested by a variety of immunologic aberrations, including increased B cell proliferation and hyper IgM and IgA secretion in vitro. Recent studies have shown that IgA secretion can be suppressed or enhanced in an isotype-specific manner by a soluble factor(s), called IgA-binding factor (IgABF), produced by IgA FcR-bearing T cells. We now show that T cells from young NZB mice, cultured with high concentrations of IgA, produce an IgABF that has aberrant biologic activity when compared to IgABF produced from IgA FcR+ T cells of BALB/c mice. Although BALB/c IgABF normally suppresses proliferation and secretion by IgA-producing B cells, neither proliferation nor IgA secretion from normal murine IgA-B cells is suppressed by NZB IgABF. In fact, IgA secretion is significantly enhanced by NZB IgABF. We also present the first evidence of IgA anti-mouse erythrocyte (anti-MRBC) autoantibody-forming cells present in the spleens of NZB mice. Whereas BALB/c IgABF suppresses the in vitro generation of IgA anti-MRBC autoantibody-forming cells by NZB spleen cells, NZB IgABF enhances this response. Of particular interest is the development of IgA anti-MRBC autoantibody-forming cells in cultures of spleen cells from nonautoimmune BALB/c mice in the presence of NZB IgABF. These studies suggest that isotype-specific T cells factors might play an important role in the development of autoantibody-forming cells.

Animals↗

Ph-negative T cells in a patient with chronic myelogenous leukemia for twenty-eight years.

The frequency of metaphases without a Philadelphia chromosome was determined in mitogen-stimulated cultures of peripheral blood mononuclear cells (PBMC) and purified T lymphocytes (93% CD2-positive) from a patient with chronic myelogenous leukemia (CML) for 28 years. The PBMC cultures contained few Ph-negative cells (8%), but they constituted 92% of the metaphases in T cell cultures, indicating few if any Ph-positive T cells in the patient's circulation. The results demonstrate that T cells derived from the leukemic clone may fail to replace the non-neoplastic population even when CML arises in childhood and the patient survives for many years. This raises questions concerning the normal role of the bone marrow as a source of T cells after infancy, and also whether Ph-positive lymphocytes may be at a disadvantage for growth.

Adult↗

Parasitic infections in Asian refugees in Fort Worth.

This report describes parasitic infections recorded from April 1984 to December 1987 in refugees using services of the Fort Worth-Tarrant County Public Health Department. Infections with 1,601 parasitic infections were documented in 824 laboratory specimens obtained from refugees. Ascariasis and giardiasis were more prevalent than other parasitic infections. The highest attack rates occurred in refugees from Cambodia (70.0%), Laos (69.7%), and Vietnam (54.3%). Information from this study supports published data on high attack rates and endemicity of infections in refugees from Southeast Asia. Continued surveillance and treatment of these refugees should improve their health conditions and prevent the development of endemic foci in the United States.

Asia↗

Modulation of Ig gene expression by Ig binding factors. Suppression of alpha-H chain and lambda-2-L chain mRNA accumulation in MOPC-315 by IgA-binding factor.

Previous reports by a number of laboratories have shown that Ig-binding factors may play a role in the regulation of Ig production by B cells. Although numerous studies have addressed the specificity and biologic function of Ig-binding factors at the cellular level, little information is available regarding the mechanism whereby Ig-binding factor modulates Ig production by B cells at the molecular level. Herein we have examined the specificity and molecular mechanism of the suppression of IgA production mediated by IgA-binding factor. Using the IgA-secreting plasmacytoma, MOPC-315, as a target cell, we have demonstrated that: 1) IgA-binding factor binds to IgA, but not to IgG, IgM, or BSA; 2) IgA-binding factor can suppress proliferation as well as IgA production by MOPC-315; 3) soluble IgA, but not IgG or IgM can inhibit the action of IgA-binding factor; 4) suppression of Ig production by IgA-binding factor is maximal within 8 to 12 h after exposure to the factor and is reversible; 5) IgA-binding factor suppresses IgA production by selectively down-regulating synthesis of IgA H and L chain proteins; 6) IgA-binding factor selectively suppresses transcription of alpha-H chain and lambda-2-L chain genes; 7) IgA-binding factor suppresses accumulation of c-myc mRNA. These findings suggest that IgA-binding factor binds selectively to surface IgA on MOPC-315 and suppresses IgA production by down-regulating transcription of H and L chain genes. Suppression of MOPC-315 proliferation by IgA-binding factor may be related to the concomitant down-regulation of the expression of the c-myc gene. c-myc is deregulated in MOPC-315 by virtue of the reciprocal 15:12 chromosomal translocation present in MOPC-315 where the c-myc gene is translocated and rearranged into the alpha-H chain gene complex. Simultaneous suppression of the expression of c-myc and alpha-H chain genes suggests that these two genes may be coordinately modulated, in plasmacytomas, by IgA-binding factor.

Animals↗

Defective T cell-mediated, isotype-specific immunoglobulin regulation in B cell chronic lymphocytic leukemia.

The consistent occurrence of T cell abnormalities in patients with B cell chronic lymphocytic leukemia (B-CLL) suggest that the non-neoplastic host T cells may be involved in the pathogenesis of this B cell neoplasm. Because potential defects of immunoglobulin regulation are evident in B-CLL patients, we investigated one aspect of this by studying the T cell-mediated immunoglobulin isotype-specific immunoregulatory circuit in B-CLL. The existence of class-specific immunoglobulin regulatory mechanisms mediated by Fc receptor-bearing T cells (FcR + T) through soluble immunoglobulin binding factors (IgBFs) has been well established in many experimental systems. IgBFs can both suppress and enhance B cell activity in an isotype-specific manner. We investigated the apparently abnormal IgA regulation in a B-CLL patient (CLL249) whose B cells secrete primarily IgA in vitro. Enumeration of FcR + T cells showed a disproportionate increase in IgA FcR + T cells in the peripheral blood of this patient. Our studies showed that the neoplastic B cells were not intrinsically unresponsive to the suppressing component of IgABF produced from normal T cells, but rather the IgABF produced by the CLL249 host T cells was defective. CLL249 IgABF was unable to suppress IgA secretion by host or normal B cells and enhanced the in vitro proliferation of the host B cells. Size fractionation of both normal and CLL249 IgABF by gel-filtration high-performance liquid chromatography (HPLC) demonstrated differences in the ultraviolet-absorbing components of IgABF obtained from normal T cells v that from our patient with defective IgA regulation. Such T cell dysfunction may not be restricted to IgA regulation, since we have found similar expansion of isotype-specific FcR + T cells associated with expansion of the corresponding B cell clone in other patients with B-CLL. These data suggest that this T cell-mediated regulatory circuit could be significantly involved in the pathogenesis of B-CLL.

Adult↗

Oxygen uptake during the gamma-irradiation of fatty acids.

The radiation-induced oxidation of saturated and unsaturated fatty acids in aqueous solutions has been estimated by measurement of the continuous uptake of oxygen using an oxygen electrode. Chain reactions, initiated by HO radicals, are easily identified to be occurring in the case of unsaturated fatty acids. Other mild oxidation agents, namely (SCN)-.2, Br-.2 and N.3, are also found to be capable of oxidizing the polyunsaturated fatty acids. Evidence is presented that O-.2 may also initiate peroxidation. The oxidation of the polyunsaturated fatty acids is dependent on dose rate, fatty acid concentration, temperature and the presence of antioxidant and other protective agents. Kinetic studies of the reaction of (SCN)-.2 and Br-.2 with linoleic and linolenic acids have been carried out using pulse radiolysis. The bimolecular rate constants for both radical species with the lipids are approx 10(7) mol-1 dm3 s-1, below their critical micelle concentrations, and decrease at higher concentrations due to micelle formation.

Cobalt Radioisotopes↗

Zinc release from irradiated yeast alcohol dehydrogenase.

The release of Zn2+ from gamma-irradiated yeast alcohol dehydrogenase has been measured using atomic absorption spectrometry. Radiolysis is accompanied by release of Zn2+ at a rate which is dependent on the nature of the free radicals available for reaction. Hydroxyl radicals and hydrogen atoms readily cause zinc release with G values of 0.13 and 0.11 (/100 eV) respectively, whereas hydrated electrons are considered not to contribute to the demetallization process. The radiolytically generated radical anions I2-., (SCN)2-. and Br2-. enhance the rate of zinc release. Evidence is presented that the enzyme is demetallized as a result of free radical reactions at cysteine and histidine residues.

Alcohol Dehydrogenase↗

Honeydew sugars in wild-caught Phlebotomus ariasi detected by high performance liquid chromatography (HPLC) and gas chromatography (GC).

Phlebotomus ariasi Tonnoir sandflies were caught in light traps hung in oak trees and in a house in the Cévennes focus of leishmaniasis in the South of France. The flies were cryopreserved either immediately on removal from the traps, or after starvation for 6-7 days, or after 6-7 days starvation followed by exposure to oak infested with the aphid genera Lachnus or Thelaxes. After transportation to the laboratory, the sandflies were thawed and aqueous extracts of the crushed flies were analysed for their carbohydrate content using high performance liquid chromatography (HPLC) and gas chromatography (GC). Starved female sandflies lacked significant amounts of any saccharides. Four types of sugar, melezitose and its hydrolysis products turanose, glucose and fructose, were observed in flies which had been starved previously and then placed with Lachnus infested oak. The results also indicate the presence of hydrolysis products of melezitose: (a) in flies previously starved and placed with Thelaxes infested oak, (b) in P.ariasi cryopreserved direct from the light traps hung in oak trees infested with Lachnus and Thelaxes, and (c) flies caught in a house. Unidentifiably small quantities of a trisaccharide were also detected in the latter groups of flies. In previous tests, sugars were detected in P.ariasi after their exposure to aphid-infested oak (Quercus ilex L.), but not when P.ariasi females were exposed to washed oak leaves without aphids. The results indicate that P.ariasi feed on melezitose and/or turanose, the main local source of which is aphid honeydew. A better understanding of sugar meal sources of sandflies using HPLC and GC techniques will assist in our understanding of sandfly/Leishmania relationships, parasite transmission and epidemiology.

Animals↗

In vitro regulation of the pathogenic autoantibody response of New Zealand black mice. I. Loss with age of suppressive activity in T cell populations.

An investigation of the regulation of specific anti-self responses was initiated with the development of an in vitro system in which spleen cells from NZB mice were stimulated by syngeneic mouse erythrocytes (MRBC) to produce MRBC-specific autoantibody-secreting cells. The response was measured by a modification of the focus-forming cell (FFC) assay, which enumerates cells secreting IgG, which specifically bind MRBC. Spleen cells from 9- to 12-mo-old NZB mice developed MRBC-specific FFC after 3 to 5 days in culture with MRBC. Few FFC were detected in the absence of MRBC in culture. Spleen cells from young (1- to 4-mo-old) NZB mice developed few if any FFC. Spleen cell populations containing T cells from young NZB mice suppressed this anti-MRBC response, whereas B cell populations from these young mice did not. In contrast, spleen cells, including T cell-enriched populations from old, Coombs'-positive mice were not capable under the same conditions of producing equivalent suppression of this in vitro autoimmune response. These data suggest that a population of suppressor T cells that may control the autoimmune anti-MRBC response in young NZB mice is lost, or else its activity is masked in old NZB mice that are actively producing anti-MRBC antibody.

Aging↗