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Biomedical subjects

D Zagury

Publications and source records attributed to D Zagury.

At least 109 records · Page 6Linked to original sources
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↗
PubMed1976

The relationship between storage and secretion of specific antibody by immune lymphoid cells: ultrastructural localization of anti-peroxidase antibodies in plaque-forming cells of the rabbit popliteal lymph node.

The ultrastructure of antibody-forming cells (AFC) has been studied in the lymph node cell population from rabbits locally immunized with horseradish peroxydase (PO) incorporated in complete Freund's adjuvant, and the kinetics of AFC development followed from day 7 to day 18 after one injection of PO. Identification of the AFC was done by local hemolysis assay, using carboxymethyl cellulose solidifying medium and PO-coated sheep erythrocytes. AFC were thereafter transferred by micromanipulation into a Beem capsule, fixed, treated by PO for fine ultrastructure detection of anti-PO antibodies, included, sectioned and studied by electron microscopy. It was found that the AFC were essentially of three categories: lymphocytes, proplasmacytes and plasmacytes, with (+), or without (-), intracellular antibody. The proportion of these categories varies with the time elapsed since the injection of antigen and with the plaque-forming activity of the population: lymphocytes (-) are relatively more numerous (over 30%) at the early stages of immunization (day 7). The number of plasmacytes increases with immunization. If most of them contain intracellular antibody at the early stages (up to day 9), the proportion of plasmacytes (+) decreases markedly afterwards. The cell type distribution is compatible with the idea that the lymphocytes are the precursors of plasmacytes, proplasmacytes being transitional forms, but no direct filiation scheme can actually be deduced from these experiments.

Animals↗
PubMed1975

[Immunocytological characterization of cells recognizing antigen and producing antibody during immunization to oxazolone and E. coli lipopolysaccharide].

A preferential cell mediated response is obtained after stimulation with oxazolone () and a humoral response is seen after E. coli lipopolysaccharide (LPS) immunization (). Thus a cytological study of selectively isolated antigen recognizing cells which form rosettes and antibody producing cells which form hemolytic plages has been performed during oxazolone and lipopolysaccharide stimulations. This investigation shows quantitative and qualitative differences of these immunocyte subpopulations in the two stimulations. First the antigen recognizing cells antibody producing cells ratio is fundamentally much higher at all the stages of the oxazolone stimulation than after lipopolysaccharide immunization. On the other hand among these immunocyte subpopulations, T and B cells are identified by electron microscopy in the oxazolone immune reaction, while only B cells are observed after LPS immunization.

Animals↗
PubMed1970

Immunoglobulin synthesis and secretion. II. Radioautographic studies of sites of addition of carbohydrate moieties and intracellular transport.

The subcellular sites of synthesis and route of intracellular transfer of immunoglobulin G (IgG) have been investigated by electron microscope radioautography with precursors used for the polypeptide chain (leucine-(3)H) and for the carbohydrate moieties (galactose-(3)H and glucosamine-(3)H). For this purpose, plasma cells from a mouse myeloma tumor were labeled with appropriate precursors and the distribution of radioautographic grains was determined at the end of the labeling period and after varying times of incubation in unlabeled medium. The results indicated that the polypeptide backbone is synthesized in a region of the cell occupied by the rough endoplasmic reticulum (RER) and is transported from there to the region of the Golgi complex. Galactose is incorporated in IgG primarily at the level of the Golgi complex, whereas the incorporation of glucosamine appears to take place both in the RER and in the Golgi complex. From the Golgi complex, the completed IgG molecules reach the plasma membrane and are discharged extracellularly. The latter route of transport and the mechanism of discharge are not understood but may be mediated via smooth-surfaced vesicles.

Animals↗