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Heslop-Harrison J, Heslop-Harrison Y. THE POLLEN-STIGMA INTERACTION IN THE GRASSES: 4. AN INTERPRETATION OF THE SELF-INCOMPATIBILITY RESPONSE. ACTA ACUST UNITED AC 2015. [DOI: 10.1111/j.1438-8677.1982.tb01660.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Heslop-Harrison
- Welsh Plant Breeding Station; Plas Gogerddan; nr Aberyswith SY23 3 EB United Kingdom
| | - Y. Heslop-Harrison
- Welsh Plant Breeding Station; Plas Gogerddan; nr Aberyswith SY23 3 EB United Kingdom
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Chapter 12 Pests, parasites, diseases and defense mechanisms of the hard clam, Mercenaria mercenaria. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0167-9309(01)80040-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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3
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Ford SE, Ashton-Alcox KA. Altered response of oyster hemocytes to Haplosporidium nelsoni (MSX) plasmodia treated with enzymes or metabolic inhibitors. J Invertebr Pathol 1998; 72:160-6. [PMID: 9709017 DOI: 10.1006/jipa.1998.4775] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To avoid phagocytosis, parasites may mask themselves with host-like molecules that prevent recognition as nonself or they may produce substances that interfere with host cellular defenses. The protozoan parasite Haplosporidium nelsoni, which causes MSX disease in the eastern oyster Crassostrea virginica, is not ingested by host hemocytes. To assess potential avoidance mechanisms, oyster hemocytes were incubated with plasmodial stages of the parasite that had been pretreated with one of a variety of enzymes (proteases and carbohydrases) to alter surface molecules or with metabolic inhibitors to prevent the synthesis or active uptake of "masking" molecules, as well as the production and discharge of inhibitory substances. The maximum increase in phagocytosis resulting from treatment with carbohydrases was 12.5% (beta-galactosidase) and with proteases was 18% (Proteinase K). Inhibitors of aerobic metabolism resulted in a similar level of enhancement. In contrast, treatment of parasites with the glycolysis inhibitor iodoacetate enhanced phagocytosis by up to 66%. Thus, the process that obstructs phagocytosis involves aerobic and, especially, anaerobic pathways. The greater effect of a metabolic inhibitor compared to enzymes suggests that the mechanism involves more than just surface modification and may include the production of interference molecules.
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Affiliation(s)
- S E Ford
- Department of Marine and Coastal Sciences and New Jersey Agricultural Experiment Station, Haskin Shellfish Research Laboratory, Rutgers University, 6959 Miller Avenue, Port Norris, New Jersey, 08349, USA
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Parish CR. Signal minus 1: a key factor in immunological tolerance to tissue-specific self antigens? Immunol Cell Biol 1996; 74:278-85. [PMID: 8799729 DOI: 10.1038/icb.1996.49] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recent data suggest that many autoreactive T cells, particularly to tissue-specific self antigens, can escape thymic deletion. The current dogma is that these autoreactive T cells are silenced by the failure of most tissues to provide co-stimulation (signal 2), antigen alone (signal 1) inducing T cell unresponsiveness. However, I propose that activation of autoreactive T cells frequently occurs but autodestruction by effector T cells is tightly regulated. This phenomenon is most evident with lymph node metastasizing tumour cells where the regional lymph node can mount a vigorous response to the invading tumour cells but tumour growth is unimpaired. I suggest that autodestruction is prevented by inhibitory receptors on T cells which recognize class I MHC structures on target cells. These receptors, which I propose deliver 'signal minus 1' to T cells, were recently described on NK cells and a subpopulation of peripheral T cells. They are also strikingly similar to a family of anti-self receptors that my laboratory described on murine T and B cells 15 years ago. In the 'signal minus 1' model, antigen-activated T cells acquire the inhibitory receptors when they become co-stimulation independent and gain the ability to exit lymphoid organs and enter non-lymphoid tissues. Thus, if autoreactive effector T cells encounter autoantigen in tissues they are functionally silenced by inhibitory receptor engagement and signal minus 1 delivery. In contrast, I propose that in response to intracellular infections, cells down-regulate expression of their ligands for inhibitory receptors. Such a model allows infected cells to be selectively eliminated by effector T cells. If correct, the model predicts that effector T cells, whether foreign-antigen- or autoantigen-specific, can selectively respond to infected cells. This apparent 'usefulness' of autoreactive T cells may explain their observed persistence even after an encounter with autoantigen. It is also suggested that signal minus 1 may silence autoreactive B cells specific for tissue-specific cell surface antigens and lack of signal minus 1 may partially explain the vigorous T cell response to allogeneic MHC. Finally, it is hypothesized that, in evolutionary terms, inhibition of autodestruction by the recognition of a 'self marker' and delivery of signal minus 1 is an ancient process which probably emerged in early metazoans.
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Affiliation(s)
- C R Parish
- Division of Immunology and Cell Biology, John Curtin School of Medical Research, Australian National University, Canberra
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Olafsen JA. Lectins: Models of Natural and Induced Molecules in Invertebrates. ADVANCES IN COMPARATIVE AND ENVIRONMENTAL PHYSIOLOGY 1996. [DOI: 10.1007/978-3-642-79847-4_4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Mansour MH. Evidence for a family of schistosome glycan-binding lectins in Biomphalaria alexandrina. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 1995; 19:365-376. [PMID: 8654664 DOI: 10.1016/0145-305x(95)00022-l] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A novel family of isolectins that selectively recognize a schistosome-associated fucosyllactose determinant was identified in the hemolymph of Biomphalaria alexandrina, a snail vector of Schistosoma mansoni. Three lectins of this family were purified by serial affinity chromatography on a column of L-fucose and elution with a gradient of 0.1-1 M L-fucose (designated BaSII and BaSIII), followed by a column of D-glucose and elution with 0.3 M D-glucose (designated BaSI). Assessment of the structural characteristics by one- and two-dimensional gels indicated that, inspite of similarities in native molecular weights, the three lectins were tetramers of noncovalently-associated subunits that were of different sizes and pIs in BaSI, and of equal size but distinct pIs in BaSII and BaSIII. Comparisons of two-dimensional gels of the glycosylated and deglycosylated forms were consistent with the presence of an invariant alpha subunit (13.2 kDa, pI 7.2) constituting the three deglycosylated lectins, which associates with other subunits unique to each lectin, namely a beta subunit (10.1 kDa, pI 5.8) in BaSI, an alpha 1 subunit (13.2 kDa, pI 6.8) in BaSII and BaSIII, and an alpha 2 subunit (13.2 kDa, pI 7.0) in BaSIII. Each of these subunits is subjected to differential post-translational N-linked glycosylations, which accounts for the additional heterogeneity expressed by the glycosylated lectins. Based on miracidial glycoprotein binding and inhibition assays, the three lectins exhibited optimum binding at similar pH and temperature, but were distinct in their binding affinities towards the fucose moiety constituting the fucosyllactose target. These observations indicate that an oligomorphic family of recognition molecules may have evolved to regulate the snails' response to schistosomes.
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Affiliation(s)
- M H Mansour
- Department of Zoology, Cairo University, Egypt
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7
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Involvement of a maternally transcribed lectin gene in the early development of Bombyx mori. ACTA ACUST UNITED AC 1994; 203:397-401. [DOI: 10.1007/bf00188688] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/1993] [Accepted: 09/21/1993] [Indexed: 11/27/2022]
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Abstract
This paper presents an overview of the evolution of defence reactions in multicellular animal life. The co-evolution of hosts and pathogens provides the context to describe the major features of defence reactions and the countermeasures they evoke in their targets. Three major types of solutions to the riddle of self-non-self discrimination are discussed briefly: non-clonal recognition mediated by lectins, the preferential accumulation of C3 in microbial surfaces and vertebrate clonal immunity. Vertebrate immunity is described as a specialized type of inflammation against infectious agents that evolved in response to countermeasures successfully used by intracellular pathogens against non-specific defences.
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Affiliation(s)
- J Quintáns
- Department of Pathology, University of Chicago, Illinois
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Abstract
Large granular hemocytes of Mercenaria mercenaria avidly phagocytose a variety of biological particles (red blood cells of six species, yeast, and gram-positive and gram-negative bacteria) as well as polystyrene spheres. Clam hemolymph is not necessary for phagocytosis but may have some opsonic effect in certain circumstances (e.g., low temperature and low particle density). Formaldehyde treatment of red blood cells enhances susceptibility to phagocytosis. Phagocytosis by Mercenaria hemocytes in vitro appears to be a nonspecific process.
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Affiliation(s)
- M R Tripp
- School of Life and Health Sciences, University of Delaware, Newark 19716
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Amirante GA. Probable role of induced lectins in capsule formation inSquilla mantis L. ACTA ACUST UNITED AC 1992. [DOI: 10.1080/11250009209386663] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Negm HI, Mansour MH, Cooper EL. Identification and structural characterization of Lyt-1 glycoproteins from tunicate hemocytes and mouse thymocytes. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1991; 99:741-9. [PMID: 1790669 DOI: 10.1016/0305-0491(91)90137-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
1. A panel of monoclonal antibodies specific to murine Lyt-1 allotypic and framework determinants was used to investigate the possible occurrence of a Lyt-1 homolog in tunicate (protochoradte) hemocytes. 2. In immunoprecipitation experiments, antigenic activities were associated with a major 67 kDa component on tunicate hemocytes and C57Bl/6 mouse thymocytes. 3. Tunicate and mouse Lyt-1 molecules were compared, in terms of glycosylation, by their sensitivity to glycosidases and analyses on one- and two-dimensional gel electrophoresis. 4. Each of the two molecules appeared to bear two N-linked oligosaccharides, one high-mannose and one complex-type glycan. 5. Both molecules revealed charge microheterogeneity with differences in sialic acid content accounting for the charge difference between each other. 6. However, the difference in the glycans did not account for the microheterogeneity within each molecule, suggesting that other post-translational modifications might be responsible. 7. At the polypeptide level, comparisons of chymotryptic and endoproteinase-Arg-C peptide maps, as well as CNBr-cleavage products, suggested that tunicate and mouse Lyt-1 molecules are structurally similar and that each may contain at least one intra-chain disulfide bridge. 8. The significance of these findings is discussed in terms of the possible biological role of Lyt-1 glycoproteins at different levels of evolution.
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Affiliation(s)
- H I Negm
- Department of Anatomy, School of Medicine, University of California, Los Angeles 90024
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Invertebrate Lectins: Biochemical Heterogeneity as a Possible Key to Their Biological Function. ACTA ACUST UNITED AC 1986. [DOI: 10.1007/978-3-642-70768-1_8] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Gunnarsson S, Lackie A. Hemocytic aggregation in Schistocerca gregaria and Periplaneta americana as a response to injected substances of microbial origin. J Invertebr Pathol 1985. [DOI: 10.1016/0022-2011(85)90074-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hopper K, Hollister W, Davey R, Semler A. Release of galactosyltransferase from peritoneal macrophages during acute inflammation. J Cell Physiol 1985; 124:137-45. [PMID: 3930517 DOI: 10.1002/jcp.1041240122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Peritoneal cells harvested from mice injected with Salmonella enteritidis or thioglycollate released large amounts of galactosyltransferase (GT), but not sialyltransferase, into their culture supernatants. Maximum release of GT (using ovalbumin as acceptor) occurred from cells harvested 2-4 days after primary injection, but little GT was released from cells elicited by a secondary injection of salmonella or ovalbumin in sensitised mice or during intraperitoneal allogeneic reactions. Enzyme release in culture did not parallel GT levels in serum. Most enzyme was released by large, poorly adherent, macrophage-enriched, Fc receptor-bearing peritoneal cells of low density. Normal monocytes, bone marrow cells, and platelets also produced large amounts, and normal spleen cells or polymorphonuclear leukocytes moderate amounts, of GT. Lymphocytes, dead cells, mast cells, red blood cells, or whole populations of lymph node and thymus cells released very low levels of enzyme. Very little GT was bound to the cell surface and was not passively absorbed from serum or platelets. Release of GT was prevented at 4 degrees C but was not markedly affected by a variety of metabolic inhibitors except pretreatment of the cells with thrombin, which increased release and trypsin which decreased release.
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Ram BP, Munjal DD. Galactosyltransferases: physical, chemical, and biological aspects. CRC CRITICAL REVIEWS IN BIOCHEMISTRY 1985; 17:257-311. [PMID: 3920003 DOI: 10.3109/10409238509113606] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Galactosyltransferases (GTs) are one of the members of a family of enzymes called glycosyltransferases involved in the biosynthesis of complex carbohydrates. These enzymes catalyze the transfer of galactose from UDP-galactose to an acceptor (glycoprotein, glycolipid) containing terminal N-acetylglucosamine or N-acetylgalactosamine residue. GTs occur in soluble (milk, serum, effusions, etc.) and insoluble (membrane) forms. The GT activities on the outer surface of the cells have been correlated with a host of cellular interactions, including fertilization, cell migration, embryonic induction, chondrogenesis, contact inhibition of growth, cell adhesion, hemostasis, intestinal cell differentiation, and immune recognition. GTs have been purified to homogeneity using affinity chromatography. Most GTs are found active in the pH range 6 to 8 and at temperatures between 35 to 40 degrees C. Manganese is an essential co-factor for GT activity. Isoenzymes of GT have been recognized, especially in tumor tissues, malignant effusions, and sera of cancer patients using polyacrylamide gel electrophoresis in the presence and absence of SDS. Depending on the source of the enzyme, the molecular weights of GTs range between 40,000 to 80,000 daltons. Carcinoma-associated GT isoenzyme has been reported to have a higher molecular weight than the normal GT isoenzyme. Development of monoclonal antibody against the cancer-specific GT isoenzyme will provide help in the development of an immunoassay for the measurement of this isoenzyme in the sera and an aid in the radioimmunolocalization of the tumors in cancer patients.
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Wago H. Cellular recognition of foreign materials by Bombyx mori phagocytes: II. Role of hemolymph and phagocyte filopodia in the cellular reactions. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 1983; 7:199-208. [PMID: 6347738 DOI: 10.1016/0145-305x(83)90001-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The plasmatocytes and granular cells are the most important hemocyte types involved in the cellular reactions of insects. These two hemocytes are obviously characterized with the adhesive morphology. Particularly, the granular cells in Bombyx mori have many long filopodia, and they are considered to play roles in catching the foreign materials invading into the hemocoel and also in obtaining some phagocytic signals during elongation process. The second part of this mini-review is a continuation of the previous summary (1) in which the immunocompetent cells in B.mori were described. Here, possible role of hemolymph factor is presented with much attention to the filopodial function of phagocytic granular cells of B.mori.
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Taneda Y, Watanabe H. Studies on colony specificity in the compound ascidian, Botryllus primigenus Oka. II. In vivo bioassay for analyzing the mechanism of "nonfusion" reaction. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 1982; 6:243-252. [PMID: 7095230 DOI: 10.1016/s0145-305x(82)80007-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Fusion experiments with three colonies (AC-BC-BD) by Tanaka and Watanabe indicated that the mixture of blood from two nonfusible colonies induced a "nonfusion" reaction (NFR)-like responses. Thus, artificial mixture of the blood from two nonfusible colonies is expected to result in NFR-like reactions. The present study deals with an in vivo bioassay using syngeneic and allogeneic blood injections. Syngeneic injection of whole blood induced no response, while allogeneic injection of whole blood induced inflammatory responses indicating recognition of allogeneic tissue. Syngeneic injection of blood plasma or blood cells induced no response. On the other hand, allogeneic injection of blood cells resulted in a response similar to that of whole blood injections. Allogeneic blood plasma induced only weak responses. It is hypothesized that NFR is initiated by the mutual interaction between blood cells and blood humoral factor(s).
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Dunphy GB, Nolan RA. A study of the surface proteins of Entomophthora egressa protoplasts and of larval spruce budworm hemocytes. J Invertebr Pathol 1981. [DOI: 10.1016/0022-2011(81)90101-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Parish CR, O'Neill HC, Higgins TJ. Glycosyltransferases and T-cell recognition. ACTA ACUST UNITED AC 1981; 2:98-101. [DOI: 10.1016/0167-5699(81)90040-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
The first part of the reversal immune surveillance hypothesis (RISH. I) describes the conceptual framework of the immune system as a homoeostatic mechanism for the control of cell differentiation and replication. The thymic dependent lymphocytes (T-cells) are considered to be tissue specific and identify aberrations in the cell surface pattern (antigens), that represent that particular cell type. The T-cells may then recruit antibody forming B-lymphocytes (B-cells) to produce antibodies (humoral response) to the cell surface antigens in order to return the cell surface pattern to its correct state. The antigens may also be removed from the cell surface as immune complexes by the complement system, which under normal conditions does not cause cell lysis. The cellular arm of the immune system, that of killer cells or activated macrophages are considered to be primarily involved with tissue remodelling. Whether or not the humoral or cellular arm of the immune system is activated depends upon the antigens displayed by the stimulating cell. The proposed system, which is self monitoring, is considered to have evolved from the invertebrates through to the vertebrates to become more complex in the mammals. Therefore the immune system is considered to be based on the identification of self and self-foreignness, rather than on foreignness per se.
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Yoshino TP. Comparison of concanavalin A-reactive determinants on hemocytes of two Biomphalaria glabrata snail stocks: receptor binding and redistribution. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 1981; 5:229-240. [PMID: 6165627 DOI: 10.1016/0145-305x(81)90030-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Komano H, Mizuno D, Natori S. Purification of lectin induced in the hemolymph of Sarcophaga peregrina larvae on injury. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)85828-3] [Citation(s) in RCA: 108] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Chorney MJ, Cheng TC. Discrimination of self and non-self in invertebrates. CONTEMPORARY TOPICS IN IMMUNOBIOLOGY 1980; 9:37-54. [PMID: 6988164 DOI: 10.1007/978-1-4615-9131-3_2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Pierce M, Turley EA, Roth S. Cell surface glycosyltransferase activities. INTERNATIONAL REVIEW OF CYTOLOGY 1980; 65:1-47. [PMID: 6993404 DOI: 10.1016/s0074-7696(08)61958-0] [Citation(s) in RCA: 81] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Abstract
The proposed reveral immune surveillance hypothesis is based on the identification primarily of self and secondarily of foreignness, unlike the original hypothesis that is based on the identification of foreignness per se. The proposed system is considered to have evolved from the invertebrates through to the vertebrates to become more complex in the mammals, and involves the identification of cell types by lymphocytes through the cell type surface pattern and major histocompatibility antigens. The identification of self and associated foreignness by the immune system is required for the regulation of cell differentiation and replication, and because of this design, the ability of the immune system to destroy foreignness can be regarded as a natural consequence. The reversal immune surveillance hypothesis explains why spontaneously occurring tumours may not be antigenic, in the sense of eliciting their own destruction, and is consistent with the destruction of tumour cells that display significant amounts of viral antigens or gross antigenic changes induced by carcinogenic agents. It is also able to explain the stimulation and inhibition of tumour development.
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Cox FE. Antimicrobial defence mechanisms in lower animals. J R Soc Med 1979; 72:638-9. [PMID: 552566 PMCID: PMC1436997 DOI: 10.1177/014107687907200903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Gorczynski RM, MacRae S, Jennings JJ. A novel role for macrophage: antigen discrimination of distinct carbohydrate bonds. Cell Immunol 1979; 45:276-94. [PMID: 466716 DOI: 10.1016/0008-8749(79)90388-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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MacDonald HR, Cerottini JC. Inhibition of T cell-mediated cytolysis by 2-deoxy-D-glucose:dissociation of the inhibitory effect from glycoprotein synthesis. Eur J Immunol 1979; 9:466-70. [PMID: 315316 DOI: 10.1002/eji.1830090610] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Previous studies have established that T cell-mediated cytolysis can be reversibly inhibited by the hexose analogue 2-deoxy-D-glucose (2-DG) by a mechanism which is apparently unrelated to energy depletion. The possibility that the inhibitory effect of 2-DG on cytolysis was linked to its known inhibitory effect on glycoprotein synthesis was therefore investigated. In contrast to the results obtained with 2-DG, no inhibition of cytolysis was observed in the presence of tunicamycin, a potent and specific inhibitor of lipid carrier-dependent protein glycosylation. Furthermore, populations of cytolytic cells which had been pretreated with doses of tunicamycin sufficient to block the incorporation of mannose (or 2-DG) into glycoproteins were still fully susceptible to inhibition by 2-DG. Other known inhibitors of viral protein glycosylation, such as glucosamine and galactosamine, inhibited cytolysis only weakly under conditions where 2-DG was highly effective. Kinetic studies revealed that the inhibitory effect of 2-DG on cytolysis could be reversed within minutes by the addition of exogenous glucose. Furthermore, suggestive evidence was obtained that inhibition cytolysis by 2-DG was linked to a parallel inhibition of effector: target cell binding. Taken together, these results strongly suggest that the inhibitory effect of 2-DG on cytolysis can be dissociated from its effect on protein glycosylation. An alternative mechanism of action of 2-DG is suggested.
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Cummings R, Cebula T, Roth S. Characterization of a galactosyltransferase in plasma membrane-enriched fractions from Balb/c 3T12 cells. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(17)34192-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Abstract
A theoretical framework is proposed for the analysis of adhesion between cells or of cells to surfaces when the adhesion is mediated by reversible bonds between specific molecules such as antigen and antibody, lectin and carbohydrate, or enzyme and substrate. From a knowledge of the reaction rates for reactants in solution and of their diffusion constants both in solution and on membranes, it is possible to estimate reaction rates for membrane-bound reactants. Two models are developed for predicting the rate of bond formation between cells and are compared with experiments. The force required to separate two cells is shown to be greater than the expected electrical forces between cells, and of the same order of magnitude as the forces required to pull gangliosides and perhaps some integral membrane proteins out of the cell membrane.
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