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C Corbel

Publications and source records attributed to C Corbel.

At least 55 records · Page 3Linked to original sources
PubMed1992

An antigen expressed by avian neuronal cells is also expressed by activated T lymphocytes.

A monoclonal antibody, anti-BEN, initially characterized by its reactivity with an epitope present on the surface of avian bursa epithelial cells and neurons, also reacts with membrane molecules on some hemopoietic cells. In this study we examine BEN expression on lymphoid cells in thymus, spleen, and blood. We demonstrate that BEN is an activation antigen on mature T lymphocytes. It is not expressed on peripheral blood or splenic lymphocytes, but following mitogenic or allogeneic stimulation of blood lymphocytes it appears rapidly on a T cell subpopulation in parallel with the appearance of IL-2 receptors. BEN is also expressed on III-C5 cells, an avian IL-2-dependent permanent T cell line, and on immature CD4+CD8+ thymocytes. BEN is not expressed by resting or actively proliferating B cells. Biochemical analyses of the BEN protein on T lymphoblasts shows that the molecule is similar in size to the BEN molecules on bursa epithelial cells and on neurons. The physicochemical properties of the BEN protein and its tissue distribution differs from other known avian and mammalian T cell activation markers, differentiation antigens, and integrins. Thus BEN is a novel marker of activated T cells in birds.

Animals↗
PubMed1992

BEN, a novel surface molecule of the immunoglobulin superfamily on avian hemopoietic progenitor cells shared with neural cells.

BEN is a novel molecule of the immunoglobulin superfamily that we previously identified by means of a monoclonal antibody on neural cell populations during avian development and epithelial cells of the bursa of Fabricius. In this paper, we describe the expression of BEN by hemopoietic cells during ontogeny. In the thymus, BEN is expressed as early as E9, and from E12 until just after hatching 30-60% of thymocytes are BEN positive. Thus the cells expressing BEN are immature thymocytes and not yet differentiated T cells. In the spleen, BEN expression parallels the myelopoietic activity. It is present on 75% of splenocytes during embryonic development and falls rapidly to 20% of cells during the first week after hatching when the spleen is becoming a secondary lymphoid organ. BEN is also found on a large proportion (about 80% positive cells) of bone marrow cells during ontogeny. Post hatching, BEN is present on 40-50% of bone marrow cells. The population of BEN-positive cells in the bone marrow includes myeloid and erythroid progenitor cells, identified by their ability to form colonies in vitro. BEN expression is lost as progenitor cells proliferate and differentiate to develop mature colonies in the clonal assay. Mature myeloid cells, such as macrophages, granulocytes, thrombocytes, and erythrocytes do not express the BEN antigen. Taken together, these data demonstrated that BEN is a stage-specific rather than a lineage-specific differentiation antigen expressed by immature hemopoietic cells.

Activated-Leukocyte Cell Adhesion Molecule↗
PubMed1992

A new marker on chicken hematopoietic cells is defined by a monoclonal antibody raised against a V beta chain of the human TCR.

In this paper, we show that a mouse monoclonal antibody, 111-427, specific for the V beta 5.3 chain of the human T-cell receptor (TCR) for antigen, also reacts with chicken hematopoietic cells. Our data indicate that the majority of 111-427 positive cells among peripheral blood leucocytes (PBL) are thrombocytes. This antibody also recognizes two in vitro cell lines, III-C5, and IL-2-dependent T-cell line and HD11, a macrophage cell line. In addition, erythrocytes and a minor subpopulation of thymus and spleen cells are also stained by the monoclonal antibody (mAb). No specific immunoprecipitation could be detected from 125I radiolabeled cell lysates. By Western blotting techniques, the 111-427 mAb identifies a single band of apparent molecular weight 91 kD, unaffected by reduction, from III-C5 and HD11 cell lysates. This band is absent in negative cell control lysates. On thrombocytes, the apparent molecular weight of the band is shifted to 87 kD. These results indicate that the mAb does not recognize the chicken T-cell receptor for antigen, but a cell surface marker shared primarily between thrombocytes and erythrocytes. This new chicken cell marker is compared to other cell surface markers in avian or mammalian species that present some analogies in their tissue distribution.

Animals↗
PubMed1991

Successful xenogeneic transplantation in embryos: induction of tolerance by extrathymic chick tissue grafted into quail.

In previous experiments, we have demonstrated that limb buds engrafted during embryonic life at E4, between MHC-mismatched chick embryos, are not only tolerated after birth, but induce in the recipient a state of split tolerance toward cells expressing the donor MHC haplotype: donor's skin grafts are permanently tolerated while a proliferative response of host's T cells is generated in MLR by donor-type blood cells. If the same experiment is performed, using quail embryo as a donor and chick as a recipient, acute rejection of the quail limb starts during the first two weeks after birth, thus suggesting that the peripheral type of tolerance induced in these experiments can be obtained only in allogeneic but not in xenogeneic combinations. We report here the unexpected result that when a chick limb bud is grafted into a quail at E4, it is tolerated and, like allogeneic grafts in chickens, induces adult skin-graft tolerance without modifying the MLR response. Similar results were obtained with grafts from another closely related species of bird, the guinea fowl from the Phasianidae family. In contrast, xenogeneic combinations involving more distant species (chick and quail as recipients and duck, an Anatidae, as donor) resulted in strong and early rejection from both recipients. As a whole, quails exhibit a greater ability than the chick to become tolerant to antigens presented peripherally from early developmental stages. In adult quails, however, skin grafts performed in either direction (i.e., quail to chick or the reverse) are rejected according to a similar temporal pattern. Moreover, lymphocytes of both species are able to respond equally well to quail or chick IL-2. Several hypotheses are envisaged to account for these observations. It seems likely that this type of tolerance is directly related to antigenic load because the load in chick to quail wing chimeras is larger than that in quail to chick chimeras. This view is supported by the protracted delay in graft rejection observed when two quail wing buds instead of one are grafted into chickens.

Animals↗
PubMed1991

[Evaluation of beta-adrenergic blockader therapy in vasovagal syncope reproduced by head-up tilt test].

Increased sympathetic tone is one physiopathological mechanism of vasovagal syncope. In this case, betablocker therapy is logical. The reports in the literature suggest that the head-up tilt test can reliably reproduce vasovagal syncope. Ten patients (4 men and 6 women, mean age 59 +/- 18 years) who suffered from recurrent vasovagal syncopes (2 to 10 attacks in 6 patients and more than 10 in the other 4) with a positive initial head-up tilt test (syncope or severe dizziness with marked hypotension after a maximum of 40 minutes at 60 degrees) were treated with atenolol (200 mg daily in 7 cases and 100 mg daily in the other 3). A second head-up tilt test was performed 15 +/- 6 days later under betablocker therapy; this test was negative in 7 and remained positive in 3 cases. Irrespective of the result, the 10 patients followed the same therapy at the same dosage. After 9 +/- 5 months, 3 patients had another syncopal attack; 2 stopped taking their medication and the third patient continued the betablocker because there was a marked reduction in the frequency of his attacks. There were no further syncopal episodes during follow-up of the other 7 patients. The medium-term efficacy could not be predicted from the results of the second head-up tilt test. The following conclusions may be drawn from this study: The head-up tilt test becomes negative in 70% of cases after introducing betablocker therapy, assuming a 100% reproductivity. This treatment is effective in over half the patients at medium term and should be considered in patients with recurrent vasovagal syncope.

Adrenergic beta-Antagonists↗
PubMed1990

[Value of the head-up tilt test in the etiologic diagnosis of syncope].

The cause of brief syncopes is discovered in only two-thirds of the cases at most. The purpose of this study was to quantify the value of the head-up tilt test in patients whose syncope remained "causeless" after a "conventional" investigation. Forty-nine patients entered the study on the following criteria: at least one syncope, no conduction disturbances or normal electrophysiological study, physiological response to carotid sinus massage, absence of postural hypotension and assessable tilt test. The head-up tilt test was performed under blood pressure and electrocardiographic monitoring in three stages: dorsal decubitus during 20 min, 60 degrees tilting during 20 min and, if nothing happened, isoprenaline injection. The test was positive (i.e. produced syncope or at least lipothymia) in 12 patients (24.5 per cent). In all cases the loss of consciousness was associated with a deep fall in blood pressure, but prolonged ventricular pause never occurred (2 patients had bradycardia at about 30 beats/min). The head-up tilt test is a non-invasive examination which in one-quarter of the cases provides a diagnosis of vasovagal syncope when no other diagnosis could be made; it reproduces the syncope, which is rarely done by other investigations, and it deserves to be include in the evaluation of unexplained syncopes.

Adolescent↗
PubMed1990

Establishment of an IL-2-dependent, antigen nonspecific chicken T-cell line.

In this article, we describe a-chicken T helper-activated cell line, III-C5, which is non-antigen-specific but IL-2-dependent. By virtue of its absolute requirement for IL-2, the III-C5 cell line is a useful tool for quantifying IL-2 production by any chicken-activated T lymphocytes in culture. The III-C5 line will be used to quantify IL-2 production in mixed lymphocyte reaction in vitro, in order to study the functional activity of T lymphocytes from avian chimeras constructed in our laboratory and particularly for studying their state of tolerance.

Animals↗
PubMed1990

Evidence for peripheral mechanisms inducing tissue tolerance during ontogeny.

Tissue grafts from a histoincompatible donor of the same developmental stage were introduced into an early chick embryo host in order to probe the immune response to the graft after birth, when the host has reached immune maturity. Limb buds from B4 or B12 chicken strains were grafted in situ on (B15 x B21)F1 recipients that were allowed to hatch. The grafted wing grew normally and was tolerated in a nearly perfect way during the host's lifetime, although reversible rejection crises severely affected the fundamentally healthy state of the grafted tissues. Skin grafts of the same major histocompatibility complex haplotype as the wing were performed on the adult wing-chimera and were permanently tolerated. In contrast, host peripheral blood lymphocytes maintained their capacity to proliferate against donor cells in the mixed lymphocyte reaction. These results, while showing that in vitro and in vivo tolerance are separable phenomena, suggest the existence of a peripheral mechanism inducing tolerance to self that complements the elimination of self-reactive clones by the thymus.

Animals↗
PubMed1989

Thymic epithelium tolerizes chickens to embryonic graft of quail bursa of Fabricius.

We demonstrated previously that isotopic and isochronic grafts of the quail bursa of Fabricius rudiment performed at 5 days of incubation (E5) into chick embryos resulted in the development of a chimeric bursa whose chick host B lymphocytes and accessory cells differentiated in a foreign, quail epithelial environment. Such animals reject their grafted bursa by the age of 2-3 weeks post-hatching (1,2). Isotopic embryonic grafts of the thymus epitheliomesenchymal anlagen from the quail donor of the bursal rudiment were carried out at E4.5 (before their colonization by hemopoietic precursor cells), following partial or complete host thymectomy. The quail thymic epithelial stroma was accepted and invaded by chick hemopoietic precursor cells that further differentiated into lymphocytes and dendritic cells. Tolerance of the foreign bursa was induced in such thymobursal chimeras. This demonstrates that the thymic epithelium has the capacity to induce tolerance of xenogeneic rudiments when both grafts are implanted at early stages of embryonic development. We also report on the production of two birds in which removal of the chick host thymus was complete thus generating chimeras in which host T and B lymphocytes differentiated in a completely xenogeneic epithelial environment.

Animals↗