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Biomedical subjects

J Charreire

Publications and source records attributed to J Charreire.

At least 91 records · Page 5Linked to original sources
PubMed1980

[Demonstration of a factor produced by human lymphoid cell lines capable of increasing murine autologous rosette formation].

The xenogeneic mixed lymphocyte culture between murine splenocytes and mitomycin-treated human lymphoblastoid Daudi cells has been shown to result in a ten-fold increase of the autologous rosette forming cells (AFRC). The supernatant from Daudi cultures enhances the ARFC population to a similar extent, in addition it induces a mitogenesis comparable to that of Con A or LPS. However these two lectins do not modify the ARFC number. Thus Daudi supernatant acts specifically on a particular subset of lymphocytes. The mechanism of induction of the ARFC is discussed.

Animals↗
PubMed1979

Morphological study of autologous rosettes (A-RFC).

The morphology of autologous rosette forming cells (A-RFC) has been studied by light and electron microscopy. Autorosette forming cells were obtained from the spleen of adult thymectomized (ATx) or nude mice, and from neonatal thymus grafts during the regeneration phase. Among the autorosettes seen by light microscopy, 76% of them were formed by lymphoid cells which included a high proportion of large lymphocytes (48%). Electron microscopy study performed after isolation of A-RFC by micromanipulation demonstrated that 74% were formed by large lymphoid cells with an immature nucleus. The finding of such large-sized lymphoid cells with immature nuclei is in agreement with our previous results indicating that A-RFC might belong to an immature T cell class.

Animals↗
PubMed1979

Regulation of contact sensitivity to DNFB in the mouse: effects of adult thymectomy and thymic factor.

The contact sensitivity response to DNFB is decreased after adult thymectomy (ATX). This response decreases to 50% of the control response of normal age-matched mice as soon as 3 weeks after ATX and is not further depressed 9 to 16 weeks after ATX. These results suggest that two T cell subsets of different lifespan are involved in the anti-DNFB response. A circulating thymic factor (FTS) is able to restore the contact sensitivity response to DNFB when injected 3 to 9 weeks after ATX but not 16 weeks later. By contrast, FTS has a depressive effect on the contact sensitivity response to DNFB of normal mice through a cyclophosphamide-sensitive T cell subset. These results suggest that FTS regulates DNFB contact sensitivity by acting on a cyclophosphamide-sensitive T cell subset, still present 9 weeks after ATX but absent after 16 weeks. Thus although the T cell defect, causing a depression of the contact sensitivity reaction to DNFB is quantitatively similar 3 and 16 weeks after ATX, its nature is probably different.

Aging↗
PubMed1978

[T-Lymphocyte regulation of contact sensitivity: effect of thymectomy in adult mice].

6 weeks after adult thymectomy (ATx) in the Mouse, the contact sensitivity reaction to dinitrofluorobenzene (DNFB) is enhanced. 4 to 7 months after ATx, this reaction is deeply, but incompletely depressed, whereas the concomitant antibody response is not affected. These results suggest that both a suppressor, and an amplifier, T lymphocytes, the life span of which is different after ATx, are involved in the regulation of contact sensitivity. The effect of circulating thymic factor on this reaction suggests that this factor acts exclusively, at least in short treatments, on the suppressor function.

Animals↗
PubMed1978

Activation of a human T cell subpopulation bearing receptors for autologous erythrocytes by concanavalin A.

Human lymphocytes from different lymphoid organs were examined for rosette formation with autologous erythrocytes. The autorosette-forming cells (A-RFC) were shown to belong to a T cell subset including less mature lymphocytes. When normal human peripheral blood lymphocytes were stimulated with low doses of the plant lectin concanavalin A (Con A), in the presence of autologous plasma, the A-RFC levels were strongly enhanced. This response gave rise to two peaks: the first one coincided with the peak of thymidine incorporation but the maximum increase occurred 5 or 6 days later when the proliferative response was impaired. Depletion of A-RFC before stimulation with Con A led to a clear-cut decrease in autorosette levels at both peaks of the response. It is concluded that Con A, generally used for polyclonal activation against heteroantigens, may also result, in terms of A-RFC marker, in expansion of an autoreactive T cell population.

Binding Sites↗
PubMed1977

Ultrastructural study of spontaneous bone marrow rosette-forming cells.

Mouse bone marrow contains spontaneous rosette-forming cells (RFC) which include more than 70% T-cell precursors, as assessed by their transformation into theta-positive cells after incubation with thymic hormone. Such spontaneous RFC, examined in C57B1/6 mouse bone marrow by electron and scanning electron microscopy, have consistently been shown to be small, inactive mouse lymphocytes when macrophages have been eliminated by cell preincubation. These data suggest that thymic hormone target cells include small quiescent lymphocytes.

Animals↗
PubMed1977

Increase in autologous erythrocyte binding by T cells with ageing in man.

Studies made of 115 normal subjects of both sexes aged 20--94 years showed that autologous rosette-forming cell levels in human peripheral blood lymphocytes were related to age and sex. However, no such relationship was found in response to phytohaemagglutinin performed in the same subjects. The nature of these autorosettes in human peripheral blood lymphocytes was studied. A significant decrease in autorosette levels was observed after passage through nylon wool at high RBC/WC ratios, and at any ratio after E-rosette depletion. The results suggesting a T-cell origin of autorosettes were confirmed by the existence of mixed autologous erythrocyte and sheep red blood cell rosettes.

Adult↗
PubMed1975

Binding of autologous erythrocytes to immature T-cells.

A small percentage of normal mouse thymus and spleen lymphocytes form rosettes with autologous erythrocytes. The number of these autologous rosettes increases 15- to 20-fold after adult thymectomy and to a lesser degree with aging. Autologous rosette level is also abnormally high in nude (congenitally athymic) mice. The high level of autologous rosette-forming cells found after adult thymectomy is normalized by injecting ng amounts of purified circulating thymic factor. Autologous rosette-forming cells adhere to nylon, belong to the less dense spleen cells, are in majority steroid-resistant in the thymus. All these properties suggest that autologous rosette-forming cells might belong to immature T-cell (thymic-dependent cell) precursors.

Animals↗
PubMed1975

Studies on B- and T-cell receptors for lysozyme.

BALB/c mice have been immunized by intravenous administration of native or reduced and alkylated lysozyme. Primary immune response to these antigens was studied at the humoral level (by the Farr assay) and at the cellular level (by the rosette and the plaque assays using lysozyme coupled to sheep or pigeon erythrocytes). Antibodies and theta-negative RFC were specific for the antigen used for immunization. Specific inhibition of theta-negative RFC after incubation with the soluble immunizing antigen confirmed this specificity. Conversely, most theta-positive RFC had double specificity both to native and denatured lysozyme and showed lower avidity for the immunizing antigen, as shown by inhibition studies with soluble antigen. These data suggest that T cells have a broader specificity for lysozyme than B cells and also that, in this particular system, cytophilic antibodies are probably not responsible for the formation of theta-positive rosettes.

Animals↗