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J Boniver

Publications and source records attributed to J Boniver.

At least 181 records · Page 10Linked to original sources
PubMed1984

Isolation of follicular dendritic cells from human tonsils and adenoids. II. Immunocytochemical characterization.

Follicular dendritic cells (FDC) are specialized cells found only within lymphoid follicles. They bind immune complexes and play a role in the presentation of antigen to follicular B cells and in the generation of B cell memory. In the present report the isolation of FDC from human tonsils and adenoids is described. These isolated cells have an unusual spherical arrangement and enclose lymphocytes within extensions of their membranes. Their ultrastructural features are similar to those observed in situ. The reactivity of isolated FDC with a number of monoclonal antibodies was analyzed by immunofluorescence and by immunostaining (at the electron microscopic level) with colloidal gold. In keeping with the results of previous investigations on tissue sections IgM, IgG and IgA (but not IgD) can be detected on the surface of isolated FDC, as can C3b receptors and the FDC-associated antigen detected by monoclonal antibody R4/23. The immunoglobulins associated with FDC are mostly embedded in an electron-dense material. The majority of the lymphoid cells enclosed within the membrane extensions of FDC are of B cell type. These results suggest that isolated FDC may be suitable for further in vitro investigation of their role in the humoral immune response.

Adenoids↗
PubMed1984

Suppression of CTL responses in vitro by large granular T cells.

The generation of large granular T cells (LGC) that display cytotoxicity similar to activated natural killer (NK) cells was described previously by the authors. To determine whether LGC can regulate the generation of allospecific CTL (C57BL/6, anti-DBA/2), we used primed responding T cells (Thy-1.2) and (Thy-1.1) to perform co-cultures. The cytolytic activities and the phenotype of the harvested T cells were examined after a co-culture period (3-6 days). We observed that the survival of fresh responding T cells was impaired in the co-cultures. Activated (4 days) responding T cells can survive in similar coculture conditions. This led to the conclusion that LGC can inactivate the CTL generation in fresh T-cell populations and that fresh and activated responding cells have different susceptibilities to LGC interactions.

Animals↗
PubMed1984

[Lympho-epithelial interactions in the thymus during development of radio-induced lymphomas in C57BL mice].

In C57BL/Ka mice, leukemogenic fractionated whole-body X-irradiation induces alterations of the lymphoepithelial interactions normally found in the Thymic Nurse Cells (TNCs) and leads to the disappearance of these complexes. This phenomenon is due to the disturbances of thymic lymphopoiesis caused by modifications of bone marrow prothymocytes and of the epithelial component of TNCs.

Animals↗
PubMed1984

Thymic nurse cells and thymic repopulation after whole body sublethal irradiation in mice.

Thymic Nurse Cells (TNCs) are lymphoepithelial complexes which are thought to play a role in the early stages of the intrathymic differentiation pathway. Therefore, their repopulation kinetics were analyzed in mice after sublethal whole-body irradiation. Changes of the number of TNCs per thymus were parallel with the evolution of the whole thymocyte population. Particularly, a first wave of TNCs restoration was followed by a secondary depletion and a final recovery. This suggests that TNCs restoration is related to the proliferating progeny of intrathymic radioresistant thymocytes. When normal bone marrow cells were grafted intravenously after irradiation, no secondary depletion was found. This pattern of restoration was obviously related to thymic repopulation by cells which were derived from the inoculated bone marrow. Homing studies with FITC labelled bone marrow cells showed that inoculated bone marrow cells did not penetrate TNCs early after irradiation. Later on, when immigrant cells started to proliferate, they were found preferentially within TNCs before spreading in the whole thymus. The results indicate that interactions between immature thymocytes and epithelial cells within TNCs are critical for the first steps of intrathymic lymphopoiesis.

Animals↗
PubMed1983

Thymic nurse cells account for the thymus dependency of preleukemic cells in mice after inoculation of radiation leukemia virus.

Inoculation of Radiation Leukemia Virus (RadLV) into C57BL/Ka mice induces thymic lymphomas after a 3-6 month latent period. The leukemogenic process requires a sequence of events from the productive infection of susceptible target cells and induction of preleukemic cells to irreversible neoplastic transformation. Preleukemic cells were detected in the thymus during the first week following virus injection. The thymus dependency of these cells was shown to depend transiently upon peculiar lymphoepithelial complexes called "Thymic Nurse Cells" (TNCs). Indeed, the first preleukemic cells appearing in the RadLV-inoculated thymuses were observed selectively within TNCs. They remained closely associated with these complexes during the first 2 or 4 weeks. Later on, TNCs disappeared almost completely whereas non-TNCs associated preleukemic cells were found. Lymphoepithelial interactions within TNCs were thus required for the initial events of RadLV-induced lymphomagenesis. The subsequent TNCs depletion expressed a disturbance of thymic lymphopoiesis in relation with the neoplastic process.

Animals↗
PubMed1983

In vitro production of granular T cells and mast cells by use of different conditioned media. Ultrastructural and functional analysis.

Normal mouse spleen cells were cultured in different conditioned media (CM). Mixed lymphocyte culture supernatant (MLC SN) was shown to promote the proliferation of cytotoxic, Thy-1+, Lyt-1+, Lyt-2+, asialo-GM-1+, weakly adherent cells with numerous vacuoles and lysosome-like cytoplasmic granules. In contrast, the Con A SN induced the proliferation of non-cytotoxic, Thy-1-, Lyt-1-, Lyt-2-, asialo-GM-1-, non-adherent cells with numerous cytoplasmic granules. The ultrastructural morphology of these cells and the cytochemical characteristics of their granules enable us to identify them as mast cells. The different effects of both CM could be related to their T-cell growth factor (TCGF) content. When the amount of TCGF of these two CM was determined (by assaying growth-stimulating activity for T-cell colonies), it appeared that the MLC SN contained larger amounts of TCGF than the Con A SN used in these experiments.

Animals↗
PubMed1983

Correlation of alkaline phosphatase activity to normal T-cell differentiation and to radiation leukemia virus-induced preleukemic cells in the C57BL mouse thymus.

Cytochemical methods at the light and electron microscopic level were used to define the pattern of alkaline phosphatase (APase) activity in normal thymus and to study its modifications after inoculation with the thymotropic leukemogenic radiation leukemia virus in correlation with the emergence of preleukemic cells and their thymus dependency. APase was found in numerous lymphoblasts of the fetal thymus. The enzyme was also detected in a few lymphoid blast cells of the normal young adult thymus, which were closely associated with thymic nurse cells. The observed distribution of APase in normal thymus suggests that its expression could be limited to an early stage of the T-cell differentiation pathway. After inoculation with radiation leukemia virus, APase activity remained normal for almost the entire latency period, during which virus replication spread to the cortex and thymus-dependent preleukemic cells appeared. An important increase in the number of APase-positive cells occurred later, i.e., at the end of the latency period, in nontumoral thymus, which displayed lymphocytic depletion and contained autonomous thymus-independent preleukemic cells. These latter features obviously reflected the malignant transformation of thymus lymphoblasts, which eventually led to the development of the thymic lymphomas. The results raise the question of the possible filiation between the thymic nurse cell-associated APase-positive lymphoid cells of the normal thymus and the target cells susceptible to productive infection and to neoplastic transformation after radiation leukemia virus infection.

Alkaline Phosphatase↗
PubMed1982

Thymic nurse cells are the first site of virus replication after inoculation of the radiation leukemia virus.

The induction of thymic lymphomas by inoculation of the Radiation Leukemia Virus (RadLV) requires interactions between RadLV, lymphoid cells and thymus microenvironment. The possible localization of this interaction within the peculiar lymphoepithelial complexes called 'thymic nurse cells' (TNCs) has been investigated. Electron microscopic studies, as well as in vitro experiments using a very sensitive infectious centre detection assay demonstrated that most of the first virus producing cells after RadLV inoculation are located within the TNCs. Most of these structures belong to the thymus subcapsular zone. They contain lymphoid cells with the phenotype of the major (cortical) thymocyte population. Data support the view that a limited subpopulation of subcapsular immature thymocyte can act as specific targets for productive infection with RadLV. Furthermore, the initiation of virus replication appears related to the interaction between the immature thymocyte and the 'nurse cells' microenvironment.

Animals↗
PubMed1982

Common proviral integration sites in C57BL mouse lymphomas induced by radiation leukemia virus and absence of novel virus-related sequences in radiogenic lymphoma DNA.

Three C57BL/Ka mice were inoculated with RadLV/VL3, a thymotropic and leukemogenic virus population released by the permanent BL/VL3 cell line, which was derived from a C57BL/Ka lymphoma induced by radiation leukemia virus (RadLV). The neoplastic thymus and bone marrow cells from these mice were grown until the cultures became permanently established, and their DNAs were examined for the presence of virus-related sequences by restriction enzyme analysis. All six cell lines displayed identical EcoRI and BamHI restriction fragments, not found in control C57BL/Ka DNA and accounting for the presence of more than one novel provirus. The primary and secondary tumors were thus clonal and, even though they were obtained from different animals, possessed identical integration sites. The BL/VL3 cell line also displayed the clonal appearance of novel proviral sequences, partly identical, with respect to location and BamHI restriction pattern, to those found in the RadL/VL3-induced tumor cell lines. Neither radiation-induced tumors, nor cloned cell lines derived therefrom, whether producing leukemogenic virus (BL/RL12-P) or not (BL/RL12-NP), displayed the presence of novel virus-related sequences when compared with control tissues. Our results strongly suggest not only that, as described in the case of avian leukosis virus-induced tumors of the chicken, RadLV-induced leukemogenesis might be a consequence of cellular gene activation by promotor insertion, but also that more than one integration site might be involved. Radiation-induced tumorigenesis might be initiated by a comparable mechanism, not requiring the participation of a virus.

Animals↗
PubMed1982

[Migration of bone marrow cells to the thymus in mice after a single sublethal-dose irradiation].

In sublethally irradiated mice, thymus repopulation is due first to the proliferation of surviving thymocytes followed by the multiplication of bone marrow derived prothymocytes. The migration of bone marrow cells to the thymus after a single sublethal whole-body X irradiation was studied by using fluorescein isothiocyanate as a cell marker. Irradiation increases the permissiveness of the thymus to the immigration of bone marrow cells. Furthermore, the post-Rx regenerating bone marrow cells exhibit migration capacities greater than the normal ones. The radiation induced changes in the bone marrow thymus interaction might play an important role in thymus regeneration after sublethal irradiation.

Animals↗
PubMed1982

[Common proviral integration sites in C57BL mouse lymphoma induced by mouse radiation leukemia virus and absence of novel proviral sequences in DNA from radiation-induced lymphoma].

Radiation leukemia virus (RadLV)-induced lymphomas of C57BL mice display the appearance of novel proviral sequences at common sites of their DNAs. These results are compatible with the hypothesis of viral oncogenesis by promotor insertion. Radiation-induced tumors do not acquire detectable novel provirus, suggesting that activation of a transforming gene proceeds by a mechanism distinct from the former.

Animals↗
PubMed1982

[Cytochemical detection and cytofluorimetric analysis of alkaline phosphatase in continuous lines of thymic lymphomas induced in mice by a radiation leukemia virus].

Alkaline phosphatase was studied in cell lines established from Radiation Leukemia Virus induced thymic lymphomas of C57BL/Ka mice. The cytochemical staining techniques and flow cytofluorimetry analysis described by Dolbeare et al. (J. Histochem. Cytochem., 1980, 28, 419-426) were used. The alkaline phosphatase found in lymphoma cells was heat labile and L-homoarginine. L-phenylalanine and p-bromotetramisole sensitive and is probably similar to the isoenzyme present in mouse placenta, kidney and liver. Very little alkaline phosphatase activity was detected in normal thymus of adult mice, suggesting that the method used in the paper could be helpful for studying the emergence of the first neoplastic cells during the leukemogenic process.

Alkaline Phosphatase↗