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R Depieds

Publications and source records attributed to R Depieds.

At least 19 recordsLinked to original sources
PubMed1979

[Existence of several non-specific recognition systems in macrophages].

Rat peritoneal cells were made to bind five particle species: immunoglobulin-coated Sheep red cells, glutaraldehyde-treated Sheep red cells, latex beads, leishmania and tumor cells. The dependence of binding on various physico-chemical parameters was studied. The binding of latex beads or Leishmania was not inhibited by cold (4 degrees C), sodium azide, cytochalasin B and ethyleneglycol or dimethylsulphoxide. The binding of immunoglobulin-coated Sheep red cells was unaffected by cold and azide, but it was inhibited by cytochalasin B, ethyleneglycol and dimethylsulphoxide. The binding of glutaraldehyde-treated Sheep red cells was inhibited by cold, azide and ethyleneglycol, but it resisted cytochalasin B and dimethylsulphoxide. The binding of tumor cells was inhibited by azide, cytochalasin B, ethyleneglycol and dimethylsulphoxide. It is concluded that: (a) macrophages are endowed several sets of non-specific binding structures that are differently affected by physico-chemical parameters, which provides a simple way of characterizing them; (b) the expression of a given binding structure on the macrophage membrane is modulated by metabolic inhibitors; (c) some lymphocytes were able to bind tumor cells or Leishmania. Thus, lymphocytes and macrophages might share some non-specific adhesive structures.

Agglutination Tests↗
PubMed1979

Evaluation of intercellular adhesion with a very simple technique.

Rosetting techniques are widely used to quantify or purify various lymphocytic subpopulations; however, these techniques cannot discriminate between different receptors of similar specificities and different binding strengths, further, they do not provide any information concerning the molecular mechanisms involved in cell-cell adhesion. This paper describes a very simple technique of assaying rosette stability: cell suspensions are driven with known pressure through a calibrated needle with a syringe. Adhesion is quantified before and after this treatment. This procedure did not damage rat peritoneal cells used in a model system. Further, this method yielded fairly reproducible results and allowed a crude estimate of the force involved in the binding of glutaraldehyde-treated sheep red cells (GSRC) or immunoglobulin-coated sheep red cells (IGSRC) by rat macrophages (an average force of 0.8 x 10(-7) Newton was needed to separate 50% of bound IGSRC from macrophages). Binding and binding strength were found to be independent parameters. Last, this method possibly provided a way of separating two distinct subpopulations of rat macrophages. It is suggested that this technique might be routinely used to refine rosette studies.

Animals↗
PubMed1979

[Macrophage receptors].

Macrophages are involved in many immunological functions such as phagocytosis, cytotoxicity, antigen binding and cooperation with lymphocytes. The triggering of those functions involves membrane receptors. Several receptors species are well characterized, but some phenomena can be accounted for only if macrophages are endowed with nonspecific adhesive structures. A study of the effect of various physical or chemical factors on the binding of several particle species by rat peritoneal macrophages allowed us to classify nonspecific receptors and discuss the mechanisms involved in some types of cellular interaction.

Animals↗
PubMed1979

Non-specific recognition in phagocytosis: ingestion of aldehyde-treated erythrocytes by rat peritoneal macrophages.

Particles were chemically modified with aldehydes and incubated with rat peritoneal cells for phagocytosis. All dialdehydes and lower monaldehydes tested (methanal, ethanal and propanal) made sheep erythrocytes phagocytosable. Failure of higher monaldehydes to induce phagocytosis of treated erythrocytes was not due to lack of reactivity with red cell membranes. All erythrocytes tested (bird and mammal red cells were used) and rat thymocytes were phagocytosed by rat macrophages after incubation with aldehyde. Treatment of Candida albicans did not induce phagocytosis: this failure was not due to lack of aldehyde binding (as demonstrated with [14C]-methanal) nor to anti-phagocytic properties of the parasite membrane. Sheep erythrocytes were submitted to enzymatic treatment (pronase, trypsin, neuraminidase) or incubated with succinic anhydride (to block free NH2 groups) or iodacetamide (to block free SH groups) before aldehyde treatment: phagocytosis was not decreased, which suggested that aldehydes did not act by altering some definite surface structure of the treated particles. Treatment of erythrocytes with cross-linking compounds such as tetraazotized o-dianisidine (coupling occurs mainly on tyrosine and histidine residues) or l-ethyl(3-dimethyl aminopropyl) carbodiimide (a bivalent reagent binding free COOH groups) did not induce any substantial phagocytosis of erythrocytes. Phagocytosis of aldehyde treated erythrocytes was partly correlated with hydrophobicity of these cells, as measured with a two-phase partition system. It is concluded that aldehyde-mediated phagocytosis of erythrocytes is mainly due to cross-linking of red cell membrane structures, probably involving free OH groups, which must increase local rigidity and thereby modify hydrophobicity of the red cell surface.

Aldehydes↗
PubMed1978

Dependence of phagocytosis on strength of phagocyte-particle interaction.

Sheep erythrocytes were pretreated with concanavalin A (Con-A-SRC), or glutaraldehyde (G-SRC), or specific rabbit immunoglobulin G (IgG-SRC), or specific rabbit immunoglobulin M and complement (C-SRC). Each erythrocyte type was made to adhere to rat peritoneal cells and adhesion was measured; binding decreased as follow: conA-SRC greater than IgG-SRC greater than less than G-SRC greater than C-SRC Peritoneal cell-erythrocyte complexes were then submitted to a laminar shear flow, and resistance of binding was assayed. Binging strength decreased in the following order: G-SRC greater than C-SRC greater than IgG-SRC greater than ConA-SRC Cell suspensions were incubated at 37 degrees, and phagocytosis was measured. Ingestion decreased in the following order: G-SRC greater than IgG-SRC greater than C-SRC greater than ConA-SRC It is concluded that: Binding strength may be of importance in triggering phagocytosis; when immunocytoadherence is studied, two independent parameters should be considered: binding and binding strength. This report describes a new method that may allow discrimination between different cell subpopulations of similar binding specificities.

Animals↗
PubMed1977

Evidence for suppressor cells in Lewis rats' experimental allergic encephalomyelitis.

In this work we demonstrate a suppressive activity on the induction of experimental allergic encephalomyelitis (EAE) in Lewis rats, transferable to syngeneic animals, challenged with encephalitogenic mixture (myelin basic protein, complete Freud's adjuvant plus Bordetella pertussis organisms) 24 h later. This activity is probably effected by T cells and not by (an) inhibitory serum factor(s). The induction of this specific protection could be due to the penetration of the myelin basic protein antigen into the thymus where we first found suppressive cells. From the thymus, suppressor cells could then emigrate to spleen (on day 15) and to nondraining lymph nodes (on day 17). In the course of normal EAE in Lewis rats and especially at the time of self cure, this suppression is not demonstrated, but possible.

Animals↗
PubMed1976

What can be measured with RAST?

A theoretical study of the basic principles involved in Radioallergosorbent test (RAST) showed that: 1) When a given serum is tested, the significance of the numerical value obtained with RAST depends upon the serum assayed and the allergosorbent preparation, in a rather unpredictable way. Three factors can be measured: a) The percentage of specific IgE antibodies among all allergen-specific antibodies; b) The specific IgE antibody level; c) The product of the specific IgE antibody level and its affinity constant. 2) Simple graphical techniques allow a straightforward determination of all these factors if four dilutions of each serum are assayed at the same time. The results are expressed in two constant parameters (arbitrary IgE unit and allergosorbent capacity). It is concluded that these theoretical calculations may give a fair account of a lack of correlation between specific IgE antibody levels (as assayed with RAST) and several clinical and biological parameters. Furthermore, they provide a simple procedure which makes such tedious manipulations as specific IgE antibody purification quite necessary.

Absorption↗
PubMed1975

Effect of concanavalin A on membrane-bound enzymes from mouse lymphocytes.

The ionic influence and ouabain sensitivity of lymphocyte mg-2+-atpase and Mg-2+-(Na+ +K+)-activated ATPase were studied in intact cells, microsomal fraction and isolated plasma membranes. The active site of 5'-nucleotidase and Mg2+-ATPase seemed to be localized on the external side of the plasma membrane whereas the ATP binding site of (Na+ +K+)-ATPase was located inside the membrane. Concanavalin A induced an early stimulation of Mg2+-APTase and (Na+ +K+)-ATPase both on intact cells and purified plasma membranes. In contrast, 5'-nucleotidase activity was not affected by the mitogen. Although the thymocyte Mg2+-ATPase activity was 3-5 times lower than in spleen lymphocytes, it was much more stimulated in the former cells (about 40 versus 20%). (Na+ +K+)-ATPase activity was undectectable in thymocytes. However, in spleen lymphocytes (Na+ +K+)-ATPase activity can be detected and was 30% increased by concanavalin A. Several aspects of this enzymic stimulation had also characteristic features of blast transformation induced by concanavalin A, suggesting a possible role of these enzymes, especially Mg2+-ATPase, in lymphocyte stimulation.

Adenosine Triphosphatases↗
PubMed1975

[Immunochemical study of liver metastases of colonic tumors].

This work demonstrated that anti-CEA and anti-NCA antibodies can be obtained from liver metastases of colonic carcinoma. The various antigens that have been identifiedin colonic tumor are found in liver metastases. Furthermore, the healthy parts of a metastatic liver contain not only CEA but also NCA.

Antibodies, Neoplasm↗