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Biomedical subjects

J Boniver

Publications and source records attributed to J Boniver.

At least 163 records · Page 9Linked to original sources
PubMed1986

The neuroendocrine thymus: coexistence of oxytocin and neurophysin in the human thymus.

Immunoreactive oxytocin and neurophysin were identified and measured by radioimmunoassay in human thymus extracts. Serial dilutions of extracts paralleled the appropriate standard curves. Thymus-extracted oxytocin and neurophysin eluted in the same positions as reference preparations on Sephadex G-75. Authenticity of oxytocin was confirmed by biological assay and high-performance liquid chromatography analysis. In most instances, thymus contents of oxytocin and neurophysin were far greater than those expected from known circulating concentrations and declined with increasing age. The molar ratio of oxytocin to neurophysin in thymus was similar to that found in the hypothalamo-neurohypophyseal system, which strongly suggested with the other data a local synthesis of oxytocin. These findings indicate the presence of neurohypophyseal peptides in the human thymus and further support the concept of a neuroendocrine function integrated in an immune structure.

Adult↗
PubMed1986

Induction of murine T cell lymphoma expressing specific cytotoxic activity.

The present work reports the establishment of an antigen-specific cytotoxic T cell lymphoma line after immortalization with a murine leukemia virus. Lymph node cells from mice bearing a transplanted syngeneic MCA sarcoma were infected in vitro with radiation leukemia virus and injected intrathymically into cogeneic recipient mice. Some lymphomas of donor origin were established as permanent continuous cell lines in vitro. One of them, NS8, expressed Thy-1.2, Lyt-1, Lyt-2 and peanut agglutinin surface markers. These cells were cytotoxic in vitro for the tumor cell line corresponding to the immunizing MCA sarcoma. No significant cytolytic activities against other syngeneic or allogeneic sarcomas or lymphomas, nor against the mastocytoma P815 were observed. After several months of in vitro propagation, the specificity of the cytotoxic activity had degraded and the level of Lyt-2 or peanut agglutinin receptors dropped. These characteristics were restored with a single in vivo passage. Thus, murine leukemia virus can be used to immortalize antigen-specific cytotoxic T cells.

Animals↗
PubMed1986

Multicellular complexes of thymocytes and different types of thymic stromal cells in the mouse.

The isolation of multicellular complexes of thymocytes and different types of thymic stromal cells from the mouse thymus is described. Isolated complexes were examined by light microscopy. Stromal cells, binding thymocytes at their surface, were identified using electron microscopy, and three types of epithelial cells, macrophages and interdigitating-like cells (IDC-like cells) were distinguished from their morphological characteristics. The epithelial cell types correspond morphologically to epithelial cells present in situ in various thymic regions. The type of thymocyte-contact with epithelial cells, macrophages and IDC-like cells indicated that the formation of multicellular complexes is common.

Animals↗
PubMed1986

In situ characterization in freeze-fractured mouse thymuses of lymphoepithelial complexes ultrastructurally similar to isolated thymic nurse cells.

Scanning and transmission electron microscopy of the cracked surfaces of cryofractured pre-fixed C57BL/Ka mouse thymus reveals the existence of cell complexes, distinct from the surrounding cell organization, in which groups of lymphocytes are delimited by large cytoplasmic sheets or envelopes. These complexes, located in the subcapsular and cortical regions, display morphological features similar to that of the thymic nurse cells (TNCs), which can be isolated from the mouse or human thymus enzymatically dissociated. They can be considered as dynamic systems able to modify their three-dimensional organization, namely with regard to intrathymic cellular traffic involved in T-lymphocyte maturation.

Animals↗
PubMed1986

Phenotype of thymic lymphomas in the mouse.

The MP2 cell line was established from a murine leukemia virus-induced thymic lymphoma. Half of the cells were consistently L3T4 positive and less than 5% of the cells were Lyt-2 positive. Single cell cloning on the basis of the presence or absence of Lyt-2 allowed the isolation of four clones with stable phenotypes: (1) Lyt-2-, L3T4-; (2) Lyt-2+, L3T4+; (3) Lyt-2-, L3T4+; (4) Lyt2+, L3T4-. These data are discussed in relation to tumour cell heterogeneity and to normal T-cell differentiation pathways.

Animals↗
PubMed1986

Cellular aspects of radiation leukemogenesis in C57 BL/Ka mice: alterations to thymic microenvironment and lymphopoiesis.

After a leukemogenic split dose course of irradiation, thymic nurse cells (TNCs) disappear. We have correlated this with the loss of an epithelial cell surface antigen (recognized by monoclonal antibody ER-TR3 and tentatively identified as Ia). In addition, epithelial cells have lost their capacity to interact with fetal thymocytes in vitro. Marrow grafting early after irradiation, that prevents the development of lymphomas, restores thymic nurse cells and thymocyte population. Such reconstitution and lymphoma prevention were not observed when marrow grafting was performed later (1 month after irradiation) during the preleukemic period.

Animals↗
PubMed1986

Effects of marrow grafting on preleukemia cells and thymic nurse cells in C57BL/Ka mice after a leukemogenic split-dose irradiation.

A split-dose regimen of whole-body irradiation (4 X 175 rad at weekly intervals) induced thymic lymphomas in C57BL/Ka mice after a latent period of 3-9 months. Meanwhile, preleukemia cells arose in the thymus and bone marrow and persisted until the onset of lymphomas. Simultaneously, thymic lymphopoiesis was impaired; thymocyte numbers were subnormal and thymic nurse cells disappeared in a progressive but irreversible fashion. The depletion of these lymphoepithelial complexes, which are normally involved in the early steps of thymic lymphopoiesis, was related to altered prothymocyte activity in bone marrow and to damaged thymic microenvironment, perhaps as a consequence of the presence of preleukemia cells. The grafting of normal bone marrow cells after irradiation prevented the development of lymphomas. However, marrow reconstitution did not inhibit the induction of preleukemia cells. They disappeared from the thymus during the second part of the latent period. At the same time, thymic lymphopoiesis was restored; thymocytes and nurse cell numbers returned to normal as a consequence of the proliferation of grafted marrow-derived cells within the thymus. The results thus demonstrated an intimate relationship between preleukemia cells and an alteration of thymic lymphopoiesis, which particularly involved the nurse cell microenvironment. Some preleukemia cells in marrow-reconstituted, irradiated mice derived from the unirradiated marrow inoculate. Thus these cells acquired neoplastic potential through a factor present in the irradiated tissues. The nature of this indirect mechanism was briefly discussed.

Animals↗
PubMed1985

Target cells and thymus microenvironment in the pathogenesis of thymic lymphomas in C57BL/Ka mice.

In C57BL/Ka mice, the induction of thymic lymphomas either by inoculation of radiation leukemia virus (RadLV) or by a split dose irradiation requires complex cellular events: Target cells are found among the population of thymic subcapsular blast cells, or, alternatively, of marrow or spleen prothymocytes; Progression of target cells to lymphoma growth requires a multi-step process, which occurs only within thymic microenvironment; Target cells are rapidly induced as "preleukemic" cells; After inoculation of RadLV, the initial events occur when target cells are in close association with cells of a specialized component of thymic epithelium, i.e., the so-called "nurse cells"; The leukemogenic agents induce damages to the thymic microenvironment itself; Lymphoma prevention by marrow grafting after irradiation results from mechanisms still unknown which inhibit the progression of "preleukemic" cells to neoplastic growth.

Animals↗
PubMed1985

Proviral genome of radiation leukemia virus: molecular cloning of biologically active proviral DNA and nucleotide sequence of its long terminal repeat.

The proviral genome of a leukemogenic and thymotropic C57BL/Ka mouse retrovirus, RadLV/VL3(T+L+), was cloned as a biologically active PstI insert in the bacterial plasmid pBR322. Its restriction map was compared with those, already known, of two nonthymotropic and nonleukemogenic viruses of the same mouse strain: the ecotropic BL/Ka(B) virus and the xenotropic constituent of the radiation leukemia virus complex. Differences were observed around the gag-pol gene junction, in the pol gene, and in the env gene. Moreover, the nucleotide sequence of the RadLV/VL3(T+L+) long terminal repeat revealed the existence of two copies of a 43-base-pair sequence, of which BL/Ka(B) possesses only one copy.

Animals↗
PubMed1985

[Specific cytotoxic activity of a virus-induced murine lymphoma].

The NS8 lymphoma induced with Radiation Leukemia Virus (RadLV) presents in vitro a specific cytotoxic activity. This line was established from a lymphoma induced by injection of lymph node cells from mice bearing the MCA-fibrosarcoma T2 to congenic mice. These cells present a cytotoxic activity limited to the T2 cells. They develop no significant cytotoxic activity against other syngeneic or allogeneic tumoral lines.

Animals↗
PubMed1985

[Ultrastructural localization of pituitary hormones by immunocytochemical reactions in ultrathin sections of adenomas].

Human pituitary adenomas were fixed in glutaraldehyde and embedded in epon. Ultrathin sections were incubated either with anti-hGH, anti-hPRL or anti-hLH. They were incubated with second step goat anti-rabbit immunoglobulins linked to gold particles. Two PRL secreting adenomas, one GH and PRL secreting adenoma, one ACTH secreting adenoma and two non secreting adenomas were studied. The specificity and the limits of the method were discussed in relation with the results obtained in light microscopy with the PAP method.

Adenoma↗
PubMed1985

[Phenotype of thymocyte populations in C57BL/Ka mice during the development of radiation-induced lymphomas].

In C57BL/Ka mice, irradiated with 4 weekly X-ray doses of 1,75 Gy, the phenotype of thymocyte populations was analyzed with monoclonal antibodies, lectins and flow cytometry. Four successive phases were defined: a) early after irradiation, a depletion of radiosensitive cortical thymocytes with a relative enrichment for radioresistant medullary type cells; b) a regeneration phase, during which thymocytes express the cortical immature phenotype; c) a third period, with a relative increase of a population with medullary phenotype; d) a late phase, during which thymocytes with the same phenotype as lymphoma cells accumulate.

Animals↗
PubMed1985

[NK activity in C57BL/Ka mice during the development of radiation-induced lymphomas].

Treatment of C57BL/Ka mice with a split dose wholebody irradiation (four weekly irradiations of 1,75 Gy) induces the development of thymic lymphomas. NK activity of spleen cells has been determined at several intervals after leukemogenic treatment. Two days after irradiations. NK activity is normal and decreases strongly after one week. This period of decline persists during about one month. Then, NK activity restores and reaches control values. Lymphomas appear in spite of NK activity restoration. The diminution of NK activity during the preleukemic period could favour preleukemic cells apparition.

Animals↗
PubMed1985

[In situ characterization of immunologically competent cells during the growth of a transplanted murine sarcoma].

To characterize the immunocompetent cell populations which infiltrate a transplantable MCA-induced sarcoma and to study their modifications during tumoral growth, we used fluorescent antibodies to the cell membrane antigens Lyt-1, Lyt-2 and Asialo GM1. Early after tumor graft, an accumulation of cells bearing the Asialo-GM1 antigen was observed; this population corresponds mostly to NK cells. Simultaneously, a macrophage infiltration, identified by a cytochemical method, was seen. After this period, an accumulation of cells bearing the Lyt-1 antigen was observed; Lyt-2 positive cells were detected continuously during experimental period.

Animals↗