Rosette Formation: The in vitro formation of clusters consisting of a cell (usually a lymphocyte) surrounded by antigenic cells or antigen-bearing particles (usually erythrocytes, which may or may not be coated with antibody or antibody and complement). The rosette-forming cell may be an antibody-forming cell, a memory cell, a T-cell, a cell bearing surface cytophilic antibodies, or a monocyte possessing Fc receptors. Rosette formation can be used to identify specific populations of these cells.Immune Adherence Reaction: A method for the detection of very small quantities of antibody in which the antigen-antibody-complement complex adheres to indicator cells, usually primate erythrocytes or nonprimate blood platelets. The reaction is dependent on the number of bound C3 molecules on the C3b receptor sites of the indicator cell.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Receptors, Fc: Molecules found on the surface of some, but not all, B-lymphocytes, T-lymphocytes, and macrophages, which recognize and combine with the Fc (crystallizable) portion of immunoglobulin molecules.Receptors, Complement: Molecules on the surface of some B-lymphocytes and macrophages, that recognize and combine with the C3b, C3d, C1q, and C4b components of complement.Immunoglobulin Fc Fragments: Crystallizable fragments composed of the carboxy-terminal halves of both IMMUNOGLOBULIN HEAVY CHAINS linked to each other by disulfide bonds. Fc fragments contain the carboxy-terminal parts of the heavy chain constant regions that are responsible for the effector functions of an immunoglobulin (COMPLEMENT fixation, binding to the cell membrane via FC RECEPTORS, and placental transport). This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme PAPAIN.Lymphocytes: White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.Receptors, Antigen, B-Cell: IMMUNOGLOBULINS on the surface of B-LYMPHOCYTES. Their MESSENGER RNA contains an EXON with a membrane spanning sequence, producing immunoglobulins in the form of type I transmembrane proteins as opposed to secreted immunoglobulins (ANTIBODIES) which do not contain the membrane spanning segment.Leukemia, Lymphoid: Leukemia associated with HYPERPLASIA of the lymphoid tissues and increased numbers of circulating malignant LYMPHOCYTES and lymphoblasts.T-Lymphocytes: Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.Complement C3: A glycoprotein that is central in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C3 can be cleaved into COMPLEMENT C3A and COMPLEMENT C3B, spontaneously at low level or by C3 CONVERTASE at high level. The smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase.Immunologic Techniques: Techniques used to demonstrate or measure an immune response, and to identify or measure antigens using antibodies.Receptors, Complement 3b: Molecular sites on or in some B-lymphocytes and macrophages that recognize and combine with COMPLEMENT C3B. The primary structure of these receptors reveal that they contain transmembrane and cytoplasmic domains, with their extracellular portion composed entirely of thirty short consensus repeats each having 60 to 70 amino acids.Binding Sites, Antibody: Local surface sites on antibodies which react with antigen determinant sites on antigens (EPITOPES.) They are formed from parts of the variable regions of FAB FRAGMENTS.Antilymphocyte Serum: Serum containing GAMMA-GLOBULINS which are antibodies for lymphocyte ANTIGENS. It is used both as a test for HISTOCOMPATIBILITY and therapeutically in TRANSPLANTATION.Sheep: Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.B-Lymphocytes: Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.Immunoglobulin G: The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.Complement System Proteins: Serum glycoproteins participating in the host defense mechanism of COMPLEMENT ACTIVATION that creates the COMPLEMENT MEMBRANE ATTACK COMPLEX. Included are glycoproteins in the various pathways of complement activation (CLASSICAL COMPLEMENT PATHWAY; ALTERNATIVE COMPLEMENT PATHWAY; and LECTIN COMPLEMENT PATHWAY).Dinitrochlorobenzene: A skin irritant that may cause dermatitis of both primary and allergic types. Contact sensitization with DNCB has been used as a measure of cellular immunity. DNCB is also used as a reagent for the detection and determination of pyridine compounds.Cytochalasin B: A cytotoxic member of the CYTOCHALASINS.Immunoglobulin M: A class of immunoglobulin bearing mu chains (IMMUNOGLOBULIN MU-CHAINS). IgM can fix COMPLEMENT. The name comes from its high molecular weight and originally being called a macroglobulin.Blood Group Antigens: Sets of cell surface antigens located on BLOOD CELLS. They are usually membrane GLYCOPROTEINS or GLYCOLIPIDS that are antigenically distinguished by their carbohydrate moieties.Complement C3b: The larger fragment generated from the cleavage of COMPLEMENT C3 by C3 CONVERTASE. It is a constituent of the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb), and COMPLEMENT C5 CONVERTASES in both the classical (C4b2a3b) and the alternative (C3bBb3b) pathway. C3b participates in IMMUNE ADHERENCE REACTION and enhances PHAGOCYTOSIS. It can be inactivated (iC3b) or cleaved by various proteases to yield fragments such as COMPLEMENT C3C; COMPLEMENT C3D; C3e; C3f; and C3g.Leukocyte Count: The number of WHITE BLOOD CELLS per unit volume in venous BLOOD. A differential leukocyte count measures the relative numbers of the different types of white cells.Plasmodium falciparum: A species of protozoa that is the causal agent of falciparum malaria (MALARIA, FALCIPARUM). It is most prevalent in the tropics and subtropics.Antigen-Antibody Complex: The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes IMMUNE COMPLEX DISEASES.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Monocytes: Large, phagocytic mononuclear leukocytes produced in the vertebrate BONE MARROW and released into the BLOOD; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles.Antigen-Antibody Reactions: The processes triggered by interactions of ANTIBODIES with their ANTIGENS.Immune Sera: Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.Phagocytosis: The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).Malaria, Falciparum: Malaria caused by PLASMODIUM FALCIPARUM. This is the severest form of malaria and is associated with the highest levels of parasites in the blood. This disease is characterized by irregularly recurring febrile paroxysms that in extreme cases occur with acute cerebral, renal, or gastrointestinal manifestations.Cell Adhesion: Adherence of cells to surfaces or to other cells.Spleen: An encapsulated lymphatic organ through which venous blood filters.Trypsin: A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.Lectins: Proteins that share the common characteristic of binding to carbohydrates. Some ANTIBODIES and carbohydrate-metabolizing proteins (ENZYMES) also bind to carbohydrates, however they are not considered lectins. PLANT LECTINS are carbohydrate-binding proteins that have been primarily identified by their hemagglutinating activity (HEMAGGLUTININS). However, a variety of lectins occur in animal species where they serve diverse array of functions through specific carbohydrate recognition.Antigens, Surface: Antigens on surfaces of cells, including infectious or foreign cells or viruses. They are usually protein-containing groups on cell membranes or walls and may be isolated.Guinea Pigs: A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.Cell SeparationLymphocyte Activation: Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.Epitopes: Sites on an antigen that interact with specific antibodies.Fluorescent Antibody Technique: Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.Thymus Gland: A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.Receptors, IgG: Specific molecular sites on the surface of various cells, including B-lymphocytes and macrophages, that combine with IMMUNOGLOBULIN Gs. Three subclasses exist: Fc gamma RI (the CD64 antigen, a low affinity receptor), Fc gamma RII (the CD32 antigen, a high affinity receptor), and Fc gamma RIII (the CD16 antigen, a low affinity receptor).Cytotoxicity Tests, Immunologic: The demonstration of the cytotoxic effect on a target cell of a lymphocyte, a mediator released by a sensitized lymphocyte, an antibody, or complement.Receptors, Immunologic: Cell surface molecules on cells of the immune system that specifically bind surface molecules or messenger molecules and trigger changes in the behavior of cells. Although these receptors were first identified in the immune system, many have important functions elsewhere.Lymphoma: A general term for various neoplastic diseases of the lymphoid tissue.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Macrophages: The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Neutrophils: Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.

Establishment of an activated macrophage cell line, A-THP-1, and its properties. (1/1162)

A new macrophage cell line with activated character and unique morphology was isolated by selecting adherent cells from the human monocytic cell line THP-1. The original THP-1 cells had been cultured for more than 9 years using 25 cm2 flasks, when cells with a different morphology appeared, adhering to the bottoms of the culture flasks. These were selected by discarding floating nonadherent cells at every subculture. Enrichment of adherent THP-1 cells with long processes proceeded during the cultivation. These adherent THP-1 showed remarkable phenotypic changes, not only morphologically, but also functionally. Namely, increased phagocytic activity, HLA-DR expression and MLR stimulator activity were remarkable. This adherent cell line was designated as activated-THP-1 (A-THP-1), since it demonstrated characteristics of activated macrophages continuously without exogenous stimulation. A cloned A-THP-1 cell line (A-THP-1 C1) also showed the same features and contained about 10% multinucleated giant cells probably caused by cell fusion. This A-THP-1 cell line, the first activated macrophage cell line to be established, provides a good model for understanding of activation mechanisms of macrophages and multinucleation. In this paper, morphological, immunological, and biological characters of this cell line are described.  (+info)

Protein kinase C and a calcium-independent phospholipase are required for IgG-mediated phagocytosis by Mono-Mac-6 cells. (2/1162)

Mono-Mac-6 (MM6) human monocytes ingest IgG-opsonized particles better than other human cell lines. We compared the phagocytic signaling pathway in MM6 with human monocytes. MM6 expressed FcgammaRI at levels similar to monocytes, whereas FcRgammaII expression was approximately double. MM6 ingested IgG-opsonized erythrocytes (EIgG) in a calcium-independent manner. Incubation of MM6 with bromoenol lactone, an inhibitor of the phagocytic phospholipase (pPL), coordinately decreased phagocytosis and pPL activity. This inhibition was overcome by exogenous arachidonic acid, suggesting that phagocytosis requires pPL activation and arachidonic acid release. MM6 phagocytosis was inhibited with staurosporine and activated with diacylglycerol, supporting a role for protein kinase C (PKC) in this process. The pPL activators mastoparan and melittin restored phagocytosis to PKC-inhibited cells, suggesting that pPL lies downstream from PKC. These results suggest that the MM6 signal transduction pathway for IgG-mediated phagocytosis is similar to that of monocytes (PKC-->pPL-->arachidonic acid-->phagocytosis). The results are discussed in the context of the finding that MM6 exhibit low phagocytosis relative to monocytes and thus may represent an attractive cell line for molecular manipulation in "recovery of function" studies.  (+info)

Identification of residues in the CH2/CH3 domain interface of IgA essential for interaction with the human fcalpha receptor (FcalphaR) CD89. (3/1162)

Cellular receptors for IgA (FcalphaR) mediate important protective functions. An extensive panel of site-directed mutant IgAs was used to identify IgA residues critical for FcalphaR (CD89) binding and triggering. Although a tailpiece-deleted IgA1 was able to bind and trigger CD89, antibodies featuring CH3 domain exchanges between human IgA1 and IgG1 could not, indicating that both domains but not the tailpiece are required for FcalphaR recognition. To further investigate the role of the interdomain region, numerous IgA1s, each with a point substitution in either of two interdomain loops (Leu-257-Gly-259 in Calpha2; Pro-440-Phe-443 in Calpha3), were generated. With only one exception (G259R), substitutions produced either ablation (L257R, P440A, A442R, F443R) or marked reduction (P440R) in CD89 binding and triggering. Further support for involvement of these interdomain loops was provided by interspecies comparisons of IgA. Thus a human IgA1 mutant, LA441-442MN, which mimicked the mouse IgA loop sequence through substitution of two adjacent residues in the Calpha3 loop, was found, like mouse IgA, not to bind CD89. In contrast, bovine IgA1, identical to human IgA1 within these interdomain loops despite numerous differences elsewhere in the Fc region, did bind CD89. We have thus identified motifs in the interdomain region of IgA Fc critical for FcalphaR binding and triggering, significantly enhancing present understanding of the molecular basis of the IgA-FcalphaR interaction.  (+info)

Plasmodium falciparum malaria: rosettes are disrupted by quinine, artemisinin, mefloquine, primaquine, pyrimethamine, chloroquine and proguanil. (4/1162)

An assay was developed measuring the disruption of rosettes between Plasmodium falciparuminfected (trophozoites) and uninfected erythrocytes by the antimalarial drugs quinine, artemisinin mefloquine, primaquine, pyrimethamine, chloroquine and proguanil. At 4 hr incubation rosettes were disrupted by all the drugs in a dose dependent manner. Artemisinin and quinine were the most effective anti-malarials at disrupting rosettes at their therapeutic concentrations with South African RSA 14, 15, 17 and The Gambian FCR-3 P. falciparum strains. The least effective drugs were proguanil and chloroquine. A combination of artemisinin and mefloquine was more effective than each drug alone. The combinations of pyrimethamine or primaquine, with quinine disrupted more rosettes than quinine alone. Quinine may be an effective drug in the treatment of severe malaria because the drug efficiently reduces the number of rosettes.  (+info)

Cytoadherence characteristics of Plasmodium falciparum-infected erythrocytes from Malawian children with severe and uncomplicated malaria. (5/1162)

Cytoadherence of Plasmodium falciparum-infected erythrocytes to the microvascular endothelium is believed to be a key factor in the development of cerebral malaria. Erythrocyte rosette formation has been correlated with malaria severity in studies from east and west Africa. We cultured fresh isolates from Malawian children with severe (n = 76) or uncomplicated (n = 79) malaria to pigmented trophozoite stage and examined rosette formation and adherence to CD36, intercellular adhesion molecule-1 (ICAM-1), chondroitin sulfate A (CSA), and thrombomodulin (TM). Most (126 of 148) isolates bound to CD36, and 76 of 136 bound to ICAM-1. Fewer bound to CSA (40 of 148) or TM (23 of 148). After controlling for parasitemia, there was an inverse association between binding to CD36 (P = 0.004) or ICAM-1 (P = 0.001) and disease severity. Parasites from children with severe malaria anemia bound least to CD36, whereas ICAM-1 binding was lowest in children with cerebral malaria. There was no difference in rosette formation between any of the groups. In Malawian children, there was no evidence of a positive association between adherence to any of the receptors examined and disease severity. The negative association found raises the possibility that adherence to certain receptors could instead be an indicator of a less pathogenic infection.  (+info)

In vivo role of complement-interacting domains of herpes simplex virus type 1 glycoprotein gC. (6/1162)

Immune evasion is critical for survival of viruses that establish persistent or recurrent infections. However, at the molecular level, little is known about how viruses evade immune attack in vivo. Herpes simplex virus (HSV)-1 glycoprotein gC has two domains that are involved in modulating complement activation; one binds C3, and the other is required for blocking C5 and properdin (P) binding to C3. To evaluate the importance of these regions in vivo, HSV-1 gC mutant viruses were constructed that lacked one or both gC domains and studied in a murine model of infection. Each gC region of complement regulation contributed to virulence; however, the C3 binding domain was far more important, as virus lacking this domain was much less virulent than virus lacking the C5/P inhibitory domain and was as attenuated as virus lacking both domains. Studies in C3 knockout mice and mice reconstituted with C3 confirmed that the gC domains are inhibitors of complement activation, accounting for a 50-fold difference in virulence between mutant and wild-type viruses. We conclude that the C3 binding domain on gC is a major contributor to immune evasion and that this site explains at a molecular level why wild-type virus resists complement attack.  (+info)

Plasmodium falciparum rosette formation is uncommon in isolates from pregnant women. (7/1162)

We examined the formation of Plasmodium falciparum erythrocyte rosettes using parasite isolates from placental or peripheral blood of pregnant Malawian women and from peripheral blood of children. Five of 23 placental isolates, 23 of 38 maternal peripheral isolates, and 136 of 139 child peripheral isolates formed rosettes. Placental isolates formed fewer rosettes than maternal isolates (range, 0 to 7. 5% versus 0 to 33.5%; P = 0.002), and both formed fewer rosettes than isolates cultured from children (range, 0 to 56%; P < 0.0001). Rosette formation is common in infections of children but uncommon in pregnancy and rarely detected in placental isolates.  (+info)

Autologous T cells control B-chronic lymphocytic leukemia tumor progression in human-->mouse radiation chimera. (8/1162)

B-chronic lymphocytic leukemia (B-CLL) is characterized by the clonal accumulation of CD5+ B cells. It has been suggested that CLL cells may be regulated by inhibitory and growth-promoting signals exerted by autologous T cells. We have recently described a model for human B-CLL in which peripheral blood mononuclear cells (PBMCs) are transplanted into the peritoneal cavity of lethally irradiated mice radioprotected with bone marrow from mice with severe combined immunodeficiency. In this model, adoptive transfer of low-stage PBMCs leads to marked engraftment of T cells or combined T and CLL cell engraftment, whereas infusion of high-stage PBMCs leads to dominance of CLL cells with a miniscule level of T-cell engraftment. This mutual exclusive pattern of engraftment indicated that T cells might control the expansion of tumor cells in the peritoneum of recipient BALB/c mice. In the present study, we further investigated this question and we demonstrate that in vivo T-cell depletion, using OKT3 antibody, markedly enhances the engraftment of B-CLL cells from patients with early-stage disease. In mice receiving PBMCs from 11 donors with advanced-stage disease, the results were more heterogeneous. In five patients the results were similar to those observed in early stage, whereas in two cases no CLL cell engraftment was found in the absence of T cells. The addition of purified T cells to PBMCs led to a substantial decrease of CLL engraftment in three advanced-stage cases. These results strengthen the working hypothesis that autologous T cells can actively suppress the expansion of the pathological cells in human-->mouse radiation chimera. This effect is prominent in early-stage disease, whereas in advanced stage suppressive and/or stimulatory effects may occur in different patients. The interaction of T cells with tumor cells and the potential of autologous T cell/immune-therapy in CLL can be further explored in this model.  (+info)

  • A marker for activated macrophages based on resistance of fc rosette formation to the inhibiting effects of anti-h2 serum. (jax.org)
  • We established a novel rosetting model by co-culturing HLA-II matched PBMCs with HL cell lines and show IS formation with activation of rosetting T cells. (rug.nl)
  • In conclusion, T cell rosetting in HL is established by formation of the IS and activation of rosetting T cells critically depends on both TCR-HLA-II and CD2-CD58 interaction. (rug.nl)
  • In particular, we have studied when the adhesive and antigenic modifications appear on the infected erythrocyte surface that mediate binding to C32 melanoma cells (cytoadherence) or to erythrocytes (rosette formation) during a complete 48-hr life cycle of the parasite. (ajtmh.org)
  • This study highlights correlation between rosette formation and altered membrane deformability of P. vivax-infected erythrocytes, where the rosette-forming infected erythrocytes are significantly more rigid than their non-rosetting counterparts. (ox.ac.uk)
  • RBCs from P. coatneyi -infected rhesus monkeys ( Macaca-mulatta ) were collected, allowed to mature overnight in vitro and found to form rosettes as hypothesized. (ajtmh.org)
  • This protocol describes an in vitro assay to monitor rosette formation by P. falciparum -infected red blood cells, including procedures for rosette enrichment, maintenance of rosetting phenotype and assays for rosetting with RBC labeled using lipophilic fluorescent probes. (bio-protocol.org)
  • By using this in vitro model of early human embryogenesis, we found that hCG/LH signal via LHCGR to promote hESC proliferation and steroidogenesis (P 4 synthesis), and that P 4 signaling is obligatory for both EB and neuroectodermal rosette differentiation. (biomedcentral.com)
  • These rosettes are polarized, transient epithelial structures that sometimes recapitulate the form of the adult organ. (biologists.org)
  • Recently, it has become apparent that polarized epithelial rosettes are common intermediates that are observed during the organogenesis of multiple organs in diverse species. (biologists.org)
  • The spindle cell subtype may be confused with the spindle cell variant of carcinoid, and epithelial thymomas may exhibit fairly pronounced rosette formation. (cap.org)
  • Sera of children with cerebral disease generally lacked anti-rosette activity, while many sera from children with uncomplicated malaria showed strong anti-rosette activity when tested against the patients' ow parasites. (ox.ac.uk)
  • Our findings suggest that apical constriction of cell membranes spatially confines regions of strong cell-cell adhesion and restricts the number of tightly interconnected cells into cellular rosettes, which ensures the correct deposition of neuromasts during morphogenesis of the posterior lateral line organ. (biologists.org)
  • Despite these differences, the many contexts in which rosettes are formed suggest that they constitute a broadly utilized mechanism during morphogenesis. (biologists.org)
  • A 36- CESA rosette was compatible with most descriptions of the microfibrils in primary cell walls up to the time of the Delmer (1999) review. (plantphysiol.org)
  • By contrast, rosettes that are formed through apical constriction can persist for extended periods of time, may or may not resolve, and often remodel to form a functional structure or organ. (biologists.org)
  • Priming with granulocyte-macrophage CSF, IL-4, or IL-5 is required for eosinophils to form rosettes with IgA-beads. (jimmunol.org)
  • In Nicole King's lab at Berkeley, however, by treating them with antibiotics-a ruthless measure to stop the choanoflagellates being overrun by bacteria-researchers found the rosettes would no longer form. (the-scientist.com)
  • Synthesis of 18-chain microfibrils is consistent with a model for cellulose-synthesizing complexes in which three cellulose synthase polypeptides form a particle and six particles form a rosette. (plantphysiol.org)
  • Whereas the intracellular mechanisms that participate in rosette formation are relatively well conserved between species and organ systems, the extracellular cues that regulate rosette formation are diverse. (biologists.org)
  • Finally, we compare and contrast the mechanisms driving rosette formation to highlight similarities and differences across organ systems. (biologists.org)
  • Generally, rosettes that are formed through the planar polarized mechanism resolve relatively quickly and typically contribute to processes involving tissue elongation. (biologists.org)
  • For example, the resolution of rosettes that are formed during convergent extension (see Glossary, Box 1 ) drives tissue elongation. (biologists.org)
  • Conclusion: DIAIH is different from AIH in liver function tests, levels of immunoglobulin and pathological characteristic such as interface hepatitis, plasma cell infiltration, portal fibrosis and Rosette formation. (alliedacademies.org)
  • These studies have revealed that the cytoskeletal rearrangements responsible for rosette formation appear to be conserved. (biologists.org)
  • ICAM-1 and CD36 are the main host cell receptors, while PfEMP1-DBLα is a major parasite ligand, which can contribute to rosette formation. (biomedcentral.com)
  • Insects that naturally attach thistle include the adult thistle-head weevil, thistle rosette weevil, thistle-stem gall fly, flower weevil, stem-mining weevil, yellow starthistle bud weevil, and yellow starthistle hairy weevil. (wikihow.com)
  • The combination of the X-ray and optical data lead astronomers to believe that stars are still forming in the central cluster of the Rosette, known as NGC 2237. (harvard.edu)
  • Astronomers study elephant trunks because of their unique formation process and use 2-D and 3-D simulations to try to understand how this phenomenon occurs. (wikipedia.org)
  • In our opinion rosettes in an osteosarcoma should be documented both from a differential diagnostic point of view and also to elucidate definitive prognostic implications. (who.int)
  • In land plants (embryophytes) and charophycean green algae, each microfibril emerges from a rosette of six particles on the plasma membrane, so it is reasonable to assume that a microfibril contains a multiple of six (1→4)-β-glucan chains, but the value of that multiple remains uncertain. (plantphysiol.org)
  • The 3′UTR of At UBP1b is sufficient to repress reporter protein expression in tissues expressing miR854 or miR855 (rosette leaves and flowers, respectively) but not where both miRNAs are absent (cauline leaves). (plantcell.org)
  • A cellulose synthesis complex with a "rosette" shape is responsible for synthesis of cellulose chains and their assembly into microfibrils within the cell walls of land plants and their charophyte algal progenitors. (plantphysiol.org)
  • This study strongly supports the "hexamer of trimers" model for the rosette cellulose synthesis complex that synthesizes an 18-chain cellulose microfibril as its fundamental product. (plantphysiol.org)