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N Thiernesse

Publications and source records attributed to N Thiernesse.

9 recordsLinked to original sources
PubMed1984

Failure to distinguish ultrastructurally between T4+ (helper) and T8+ (suppressor/cytotoxic) T-cell subsets.

Human peripheral T-cell subpopulations revealed by monoclonal antibodies by means of a rosetting method were isolated by micromanipulation and submitted to electron microscopic analysis. The T3+ subset (total T cells) displayed a high degree of heterogeneity, including multiple transitional forms, from cells with a high nuclear to cytoplasmic ratio and rare organelles to cells with a low nuclear to cytoplasmic ratio and a complex system of cytoplasmic organelles. T4+ (inducer/helper) and T8+ (suppressor/cytotoxic) cell subpopulations were shown to have no evident distinguishing characteristics. They both displayed the same morphological variation mentioned for T3+ lymphocytes. On morphometric analysis, these two cell subsets were very similar, with only slight differences for cell surface roughness, volume of mitochondria, extent of nuclear indentation, and surface area of the rough endoplasmic reticulum. The significance of these minor morphological differences is discussed.

Animals↗
PubMed1981

Inhibition of T cell-mediated cytolysis by monoclonal antibodies directed against Lyt-2: heterogeneity of inhibition at the clonal level.

The inhibitory effect of monoclonal anti-Lyt-2 antibodies on T cell-mediated cytolysis has been investigated at the clonal level. In agreement with previous reports from several laboratories, populations of cytolytic T lymphocytes (CTL) generated in vitro in mixed leukocyte cultures (MLC) were reversibly inhibited by monoclonal anti-Lyt-2 antibodies in a dose-dependent fashion. However, when alloimmune peritoneal exudate lymphocytes (PEL) were used as a source of CTL, little or no inhibitory effect of anti-Lyt-2 antibodies on cytolysis was observed. A series of CTL clones derived from MLC or PEL populations was also tested for inhibition of cytolysis by anti-Lyt-2 antibodies. In agreement with results obtained at the population level, most MLC-derived clones (81%) were strongly inhibited by the reagent, whereas few PEL clones (15%) were inhibited. Several of these clones were expanded and maintained in culture without loss of their "inhibition phenotype." Flow cytofluorometric analysis using the same monoclonal anti-Lyt-2 antibodies further revealed that both inhibited and uninhibited clones expressed comparable amounts of Lyt-2 antigen. These results provide direct evidence that inhibition of CTL by anti-Lyt-2 antibodies is heterogeneous at the clonal level. The possibility that this heterogeneity may be related to avidity of antigen receptors is discussed.

Animals↗
PubMed1979

[Is the process of localized lysosomal exocytosis responsible for the cytolytic action of killer T-lymphocytes?].

In this paper, we formulate the hypothesis that in the process of target cell lysis a lysosomal enzyme regurgitation, performed by killer cells at the level of the target effector junction, accounts for the target lesion which precedes the lysis (lethal hit). This process of exocytosis, similar to the one described previously in polymorphonuclear neutrophils is supported by cytological studies performed directly on identified killers isolated by micromanipulation. Light and electron microscopy observations confirm a previous report which describes the effector cells rich in lysosomal bodies. In addition, when a killer cell is associated with a target cell to form a conjugate, lysosomes are concentrated near the cell junction and, after incubation at 37 degrees C, acid phosphatases may be detected at the junction. Lysosomal enzyme exocytosis explains why target lysis needs an effector target binding to occur and also the other conditions required for any exocytosis process such as Ca++ in the medium, integrity of the microtubular apparatus, a low level of cyclic AMP and energy dependancy.

Acid Phosphatase↗
PubMed1979

Subpopulations of Ig-secreting cells induced by peroxidase immunization: discrimination according to antibody storage and secretion.

Mice were injected in their hind footpads with peroxidase (PO) emulsified in Freund's complete adjuvant. The development of cells secreting anti-peroxidase antibody (Ab) and cells secreting immunoglobulins (Ig) were detected in the draining popliteal lymph nodes in the subsequent 35 days, using local haemolysis plaque assay with sheep red cell blood cells coated with either PO or anti-mouse Ig antibody. Plaque-forming cells (PFC) were isolated from the centre of plaques by micromanipulation and after appropriate treatment, were examined by electron microscopy for their intracellular Ab content and in corporation of [3H]-thymidine. Four subpopulations of Ig secreting cells were distinguished: (1) cells secreting Ig without Ab function and not containing intracellular Ab detectable between days 5 and 20; (2) cells secreting Ig without Ab function but containing Ab appearing on day 6 and present throughout the immune response; (3) cells secreting Ab and containing Ab; (4) cells secreting Ab, but without detectable intracellular Ab. These last subpopulations appeared on day 7 and were found in all subsequent assays. The analysis of the kinetics of these subpopulations suggest that cells secreting Ig without Ab function might be precursors of Ab secreting cells.

Animals↗
PubMed1978

Classical and alloimmune anaphylactic degranulation of isolated single mast cells.

Viable mast cells, directly isolated by micromanipulation from a mouse peritoneal cell suspension, were deposited on the bottom of microtiter-plate wells and submitted to histamine release. Conventional antigen-induced anaphylactic degranulation as well as direct allogeneic anaphylactic degranulation were strongly inhibited when these mast cells were settled on normal tissue culture plastic surfaces. Nevertheless, normal degranulation could be recovered by pretreatment of the experimental surface with a multipositive charged molecule (poly-L-lysine). Under these conditions, we demonstrate that the degranulation of one isolated mast cell is possible and consequently, as regards the direct allogeneic anaphylactic degranulation, confirm the "self-triggering mechanism" in which the recognition of histocompatibility antigens on the membrane of the mast cell itself is the trigger to the secretory response. The technique of monocellular degranulation described in this paper provides a new tool which leads us to think that the problem of detection of anaphylactic antibody-secreting cells can be solved.

Anaphylaxis↗
PubMed1977

[Acid phosphatase activity of cytolytic T cells during cytolysis].

The localization of Golgi areas, particularly lysosomal bodies detected by their acid phosphatase activities, has been determined in the cytotoxic lymphocytes conjugated to their target cell. The study points out the preferential situation of these organelles close to the contact area between the two cells during the target cell lysis.

Acid Phosphatase↗