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ABSTRACT: Lymphoid cell subpopulations involved in allograft rejection in the teleost Dicentrarchus labrax were characterised at the ultrastructural level and quantified by using monoclonal antibodies against T- and B-lymphocytes. T-cells positive for T-cell receptor beta-chain (TcR beta) were detected by reverse transcription/polymerase chain reaction (RT-PCR) and in situ hybridisation by using RNA probes for TcR beta. Flow cytometry detected a similar percentage of T- and B-lymphocytes (around 17%) in the leucocyte-enriched fraction from allografts. Two different types of T-lymphocytes (DLT 15-immunoreactive) infiltrating the allografts were identified by cytomorphology: small cells with high nuclear/cytoplasmic ratio and cells with a higher cytoplasmic content. RT-PCR revealed a single band (513 bp) corresponding to the TcR beta. In situ hybridisation showed that TcR beta-positive cells in the grafted muscle fibres were less numerous compared with DLT 15-positive cells, as evidenced in parallel sections, suggesting that cytotoxic cells might express different TcR phenotypes. DLIg 3-immunoreactive Ig-producing lymphocytes had: 1) a high nuclear/cytoplasmic ratio or 2) a larger size similar to that of pre-plasma cells (plasma cells lacked any membrane labelling).
Cell and Tissue Research 10/2005; 321(3):353-63. · 3.11 Impact Factor
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ABSTRACT: Species that live in extreme conditions have specially adapted physiology and tissue/organ organisation. The adaptation of lymphoid organs to low temperatures in polar species could be an original field of study, indicating how the immune system works under extreme conditions. In fishes, the head kidney is a key organ for immunity and here the cytology of this organ is studied in two common Antarctic species: Trematomus bernacchii and Chionodraco hamatus. Ultrastructural analysis revealed heterogeneity of epithelial cells, with reticular cells, subcapsular- and perivascular-limiting cells. Differences in the size and morphology of epithelial cells were observed between the polar species and warm water species of fish. Intermingled with epithelial cell leucocytes, such as lymphocytes, thrombocytes and macrophages, had comparable morphology in both species, contrary to sharp differences observed in the morphology of erythrocytes and granulocytes. The functional adaptation of the head kidney to the low temperatures of polar water is discussed.
Tissue and Cell 05/2002; 34(2):63-72. · 1.04 Impact Factor
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ABSTRACT: Monoclonal antibodies which recognize antigenic determinants expressed by T-cells and Ig-bearing cells, respectively, allowed lymphocyte subpopulations involved in allograft rejection of muscle transplants to be identified in the teleost fish Dicentrarchus labrax (L.). The monoclonal antibody DLT15 first allowed recognizing T-cells involved in an in vivo antigen-driven cellular response in teleosts. Immunohistochemical studies showed a high density of lymphocytes in allografts and provided evidence of predominance of T-cells. The heterogeneity of the cell populations recognized by the antibodies was evidenced by the different size, cytology, and staining patterns of T-cells and Ig-bearing cells.
Cellular Immunology 03/1999; 191(2):152-60. · 1.97 Impact Factor
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ABSTRACT: The structure of the developing thymus of the marine teleost, Diplodus puntazzo, was studied by light and transmission electron microscopy. The first anlage of the thymus developed by d 20 postfertilisation (p.f.) as a group of undifferentiated cells dorsal to the epithelium of the branchial chamber. The organ increased significantly in size around d 51-66 p.f. and differentiation of cortex and medulla occurred concomitantly. On the basis of their localisation, 4 main types of epithelial cell were distinguished: (1) limiting, adjacent to the connective capsule; (2) medullary and cortical reticular cells; (3) nurse cells, located in the corticomedullary boundary; (4) Hassall-like corpuscles. The majority of medium to large blast-like lymphoid cells were localised in the medulla, while small lymphocytes were housed in the cortical region. These morphological features were maintained at later stages. However, in juveniles in the medulla we observed reticular epithelial cells with cysts and rare Hassall-like corpuscles. The study was designed to obtain more information concerning the histology of the developing thymus of sharpsnout seabream and give a concise description of the differentiation of epithelial cells and lymphoid cells in the thymic parenchyma.
Journal of Anatomy 02/1999; 194 ( Pt 1):39-50. · 2.37 Impact Factor
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ABSTRACT: A monoclonal antibody against carp macrophages (WCL15) has been utilised in flow cytometry, immuno-histochemistry and immuno-electron microscopy to assess the distribution of monocytes/macrophages in developing carp lymphoid tissues. In suspensions of living cells WCL15 reacted strongly with cytoplasm and plasmic membrane of macrophages. It also cross-reacted with a subpopulation of thrombocytes, but this reaction could be neglected by double immunostaining in combination with a thrombocyte-specific marker. In Bouin-fixed tissues the antibody distinctly recognised macrophages. Macrophages were found from day 2 post-fertilisation in head kidney and in the dorsal portion of the yolk sac epithelium. From 1 week onwards macrophages were found scattered in thymus and gut and during the second week in spleen. Macrophages increased in number in all lymphoid tissues until the 6-8th week post-fertilisation, but they decreased except in thymus, where they became localised mainly in the cortical-medullary boundary, and in white pulp areas of head kidney. The role of macrophages in allowing an early non-specific defence in young fish and in co-operating during the differentiation processes of T-cells and B-cells is discussed.
Anatomy and Embryology 08/1998; 198(1):31-41. · 1.42 Impact Factor
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ABSTRACT: The monoclonal antibodies DLT15 and DLIg3, which recognize antigenic determinants expressed by T cells and Ig-bearing cells, respectively, allowed the development of gut-associated lymphoid tissue of the teleost fish Dicentrarchus labrax (L.) to be studied. DLT15-immunoreactive cells were first detected in the epithelium of the stomach and intestine at day 30 post-hatching of fish maintained at 16 degrees C. At that age, positive cells were found only in the thymus. Between day 44 and day 81 post-hatching, DLT15-immunoreactive cells became numerous, both in and under the gut epithelium. A gradient in the number of lymphocytes was present, concentrating them towards the anus. Until day 81 post-hatching, DLIg3-immunoreactive cells were not found in the gut, although they were present in the kidney, spleen and thymus earlier. Infrequent Ig-bearing cells were found in the gut mucosa of -year-old sea bass. This study showed that the gut-associated lymphoid tissue developed earlier than other lymphoid compartments. It also provided evidence of the predominance of T cells in the gut immune system of the sea bass.
Anatomy and Embryology 01/1998; 196(6):457-63. · 1.42 Impact Factor
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ABSTRACT: The monoclonal antibodies DLT15 and DLIg3 directed against thymocytes and serum immunoglobulins of the sea bass (Dicentrarchus labrax, L.) were used to study cells from the thymus, head kidney, spleen, gut-associated lymphoid tissue and peripheral blood leukocytes of this fish by immunofluorescence and pre-embedding immunoelectron microscopy. Immunofluorescence and flow cytometry of leukocyte fractions revealed a large number of DLT15-positive cells in the thymus (approximately 80%) and intestine (approximately 55%) and fewer cells in the spleen (approximately 7%), head kidney (approximately 6%) and peripheral blood (approximately 3%). DLT15-positive cells had two main morphologies, both detectable among thymocytes: a large round heterochromatic nucleus with light sparse cytoplasm (type a) and an irregular and heterocromatic nucleus with cytoplasm rich in polysomes and mitochondria (type b). Type b was most represented in spleen, head kidney, intestine and blood. We suggest that the type b morphology represents more differentiated lymphocytes. Flow cytometry revealed numerous DLIg3-positive cells in the head kidney (approximately 33%), spleen (approximately 30%) and peripheral blood leukocytes (approximately 21%) and fewer positive cells in the intestine (approximately 3%) and thymus (approximately 2%). DLIg3-positive cells had the morphology of lymphocytes (with a large round nucleus) or macrophages in all tissues. Plasma cells lacked membrane immunoreactivity. This is the first ultrastructural characterisation of putative T- and B-lymphocyte subpopulations in a fish species; these subpopulations are differentially distributed in teleost lymphoid organs.
Cell and Tissue Research 08/1997; 289(1):163-71. · 3.11 Impact Factor
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ABSTRACT: The thymus of 18-day-old normal-chick embryos, partially decerebrated chick embryos, and partially decerebrated embryos bearing hypophyseal allografts were analysed by light and transmission electron microscopy. The hypophyseal influence on the cytological differentiation of epithelial components has been studied. The thymus of partially decerebrated embryos showed a delayed differentiation of some types of epithelial cells and a marked decrease in number of lymphoid cells. Partially decerebrated embryos with hypophyseal implants showed a consistent recovery in the degree of differentiation of epithelial components. These findings indicate the influence of the hypophysis in establishing a correct environment for stromal cell differentiation.
Anatomy and Embryology 07/1996; 193(6):593-600. · 1.42 Impact Factor
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ABSTRACT: Histology demonstrated chromaffin cells in the head kidney and opisthonephros of the sea bass. Immunohistochemistry showed the catecholamine-synthesizing enzymes tyrosine hydroxylase and dopamine beta-hydroxylase in these cells. Phenlethanolamine N-methyltransferase was detected in a fraction of the chromaffin cells in the head kidney (59%) and in the opisthonephros (54%). Distinct noradrenaline- and adrenaline-synthesizing cells are therefore suggested. Ultrastructural analysis confirmed the existence of two main chromaffin cell types, distinguished by different types of the secretory granules. Cells that contain vesicles with a round, electron-dense core were interpreted as noradrenaline cells, while cells with electron-lucent vesicles were identified as adrenaline cells. The ultrastructure of these chromaffin cell subtypes does not differ in the head kidney and opisthonephros. A minor population of chromaffin cells was identified, which typically show smaller vesicles with an electron-dense core. This population may account for a limited number of not fully differentiated chromaffin cells.
General and Comparative Endocrinology 05/1996; 102(1):113-22. · 3.27 Impact Factor
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ABSTRACT: The bursa of Fabricius of 18 day normal and partially decerebrated chick embryos, and partially decerebrated embryos bearing a hypophyseal allograft was analysed by scanning and transmission electron microscopy, focusing on the ultrastructural characterisation of the plical epithelium. The plicae of the normal bursa consist of interfollicular (IFE) and follicle associated epithelium (FAE). The FAE is composed of typical polygonal cells and is supported by a layer of epithelial cells which appears as a continuation of the corticomedullary epithelium. Bordering cells lie between the FAE and IFE. The IFE is composed of 4 cell types: (1) undifferentiated, (2) goblet, at various stages of maturity, (3) prismatic, and (4) globular light cells. Partially decerebrated embryos showed a gross impairment of plical epithelium development and the complex of FAE and IFE cells was largely undifferentiated. Partially decerebrated embryos with a hypophyseal allograft displayed the same cellular types as observed in controls, thus indicating a restored differentiation of plical epithelium. These findings suggest that the hypophysis affects the differentiation of plical epithelium during ontogenesis.
Journal of Anatomy 03/1996; 188 ( Pt 1):29-41. · 2.37 Impact Factor
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ABSTRACT: Adrenal chromaffin cells in the head kidney of the stickleback Gasterosteus aculeatus were examined by ultrastructural analysis and determination, by HPLC, of the catecholamine content (adrenaline, noradrenaline, and dopamine). Chromaffin cells are characterized by the presence of membrane-bound vesicles and two cell types were identified: (i) those with vesicles containing a strongly electron-dense core; and (ii) those with vesicles that are completely electron lucent or containing smaller and less-dense granules. HPLC analysis revealed the presence of adrenaline and noradrenaline in both right and left head kidneys. Dopamine was not detected. Cytological and biochemical data suggest that the cells with electron-dense granules contain noradrenaline and those with electron-lucent vesicles contain adrenaline.
General and Comparative Endocrinology 12/1993; 92(2):133-42. · 3.27 Impact Factor
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ABSTRACT: The ultracytochemical localization of the enzyme acetylcholinesterase (AChE) was studied in the germinal epithelium and cortex during chick ovarian morphogenesis at the 7, 12.5, 14 and 19 day of incubation. The results evidenced at day 7 the presence of the enzyme in some somatic cells, both "dark" and "light" and in some gonocytes. The reaction appears also in some tracts between these types of cells. At day 12.5 the reaction is present in some somatic cells only towards the deepest zone of the cortex, in many oogonia and oocytes and in some tracts between germ and somatic cells. At day 14 and day 19 the various cell categories of the cortex are negative for the reaction. The significance of the presence of the enzyme is discussed in relation to an embryonic cholinergic system active during morphogenesis. Regarding the presence of the enzyme in germ cells, the positivity in endoplasmic reticulum cisternae associated to mitochondria may suggest an implication of the enzymatic activity in the proliferation and transformation of these organelles.
Cellular and molecular biology 02/1990; 36(5):497-508. · 0.98 Impact Factor
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ABSTRACT: The presence of acetylcholinesterase (AChE) activity in the adrenal chromaffin cells of Necturus maculosus and Ambystoma maculatum (Amphibia, Urodela) has been demonstrated by cytochemical method at the electron microscope level. The enzymatic activity is localized in RER and perinuclear cisternae, on the plasma membrane and within the chromaffin vesicles, both in adrenaline (A) and noradrenaline (N) cells. Moreover N cells appear to be more reactive than A cells and Necturus more reactive than Ambystoma. The possible function of the AChE activity inside the vesicles is discussed as a mechanism of protons donor or as peptidasic activity acting on various peptides present in the vesicle.
Cellular and molecular biology 02/1989; 35(3):247-53. · 0.98 Impact Factor
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ABSTRACT: The cytochemical localization of acetylcholinesterase (AChE) activity was studied in the adrenal chromaffin cells of Discoglossus pictus. Reaction end-products were associated with all types of chromaffin cells, i.e. adrenaline (A), noradrenaline (N) and small granule chromaffin (SGC-A, SGC-N) cells, and nervous elements present in the gland. The SGC-A and SGC-N showed the same intensity of AChE reaction in A and N cells, respectively. On the whole, the A and SGC-A cells were more reactive than the N and SGC-N cells. The functional role of the SGC cells is discussed on the basis of the cytochemical results.
Basic and applied histochemistry 02/1987; 31(2):135-42.
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ABSTRACT: The ultracytochemical localization of acid phosphatase was studied in oogonia and oocytes of the chick embryo left ovary. The reaction products are evident in lysosomes of various types and, in some cells, in the GERL as well. Furthermore, from the onset of the meiotic prophase, the enzymatic reaction also appears in the rough endoplasmic reticulum. Non-incubated sections of the same stages were observed, with the aim of identifying and describing the structure of the organelles, in particular lysosomes which appeared positive in incubated sections. The significance of the presence of the enzyme is discussed.
Experimental cell biology 02/1986; 54(2):94-105.
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ABSTRACT: The distribution of acetylcholinesterase (AChE) and pseudocholinesterases (PsChE) in chick adrenal gland during the first phases of organogenesis was studied. Acetylthiocholine iodide and butyrylthiocholine iodide were used as substrates for the two enzymes, respectively, whereas BW284c51 (1,5 bis (4-allyldimethylammonium-phenyl)pentan-3-one-dibromide) and ISO-OMPA (tetraisopropylpyrophosphoramide) were used as respective inhibitors of AchE and PsChE. AchE was present on the plasma membrane, in the perinuclear cisterna and in some cisternae of the rough endoplasmic reticulum of both interrenal and chromaffin cells; moreover enzymatic activity was found in the same sites of ganglion cells and mesenchymatic undifferentiated cells, i.e. on the inside and in the proximity of the glandular anlage. PsChE activity was localized in the perinuclear space and in the rough endoplasmic reticulum of all types of cells in the anlage. It is suggested that these enzymatic activities may be implicated in morphogenetic mechanisms.
Basic and applied histochemistry 02/1986; 30(1):97-108.
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Cellular and molecular biology 02/1986; 32(5):511-7. · 0.98 Impact Factor
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ABSTRACT: The chromaffin cells of the adrenal homologue of Salmo gairdneri R. have been studied by light and electron microscopy. The chromaffin tissue was localised in the head kidney adjacent to the wall of the proximal part of the cardinal veins and their main branches. Specific histochemical techniques failed to demonstrate different types of chromaffin cells. With the electron microscope two different types of chromaffin cells were observed. The first type, characterised by numerous dense cytoplasmic granules of average diameter 90 nm, was interpreted as a noradrenalin cell; the second type was characterised by the presence of moderately electron-dense granules of average diameter of 85 nm, and was interpreted as an adrenalin cell. The reaction for acetylcholinesterase activity was present on nerve terminals and sometimes in the vacuolar membrane systems of both chromaffin cells.
Journal of Anatomy 06/1984; 138 ( Pt 3):503-11. · 2.37 Impact Factor
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Cellular and molecular biology 02/1983; 29(2):159-68. · 0.98 Impact Factor
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Acta embryologiae et morphologiae experimentalis ("Halocynthia" Association") 08/1982; 3(1):29-39.
