Search PubMed⌕ Search

Biomedical subjects

M Dy

Publications and source records attributed to M Dy.

At least 109 records · Page 6Linked to original sources
PubMed1978

[Effect of lymphokines produced in a grafted system on production of prostaglandins by macrophages].

Mice peritoneal macrophages cultured in vitro release a prostaglandin-like activity as evaluated by a bio-assay using Rat stomach fundus. The prostaglandin release is greatly increased when macrophages are incubated with the supernatant of mixed lymphocyte cultures between recipient and donor of a skin allograft. This phenomenon was found in all strains of Mice tested except C3H/HeJ Mice, a strain already known for its defective responsiveness to bacterial lipopolysaccharide (LPS).

Animals↗
PubMed1978

[Production of prostaglandins in mixed lymphocyte cultures (MLC) between allograft donors and recipients].

A prostaglandin-like activity, as evaluated by a bio-assay using the fundus of Rat stomach, has been demonstrated in supernatants of lymphocyte cultures. This activity undergoes a striking increase in supernatants of mixed cultures of allograft donor and recipient cells, when compared with control supernatants of donor or recipient cells cultured alone. This phenomenon is observed after 24 hrs. of culture. It disappears if the supernatant is dialyzed. Little or no increase in prostaglandin-like activity is found in supernatants of primary mixed lymphocyte cultures (without previous allograft), at lest in the first two days of culture.

Animals↗
PubMed1978

[Cytotoxicity of mouse peritoneal cells after alloimmunization].

CBA Mice were immunized by two intraperitoneal injections of 30 X 10(6) DBA/2 or C57BL/6 spleen cells at days--12 and--2. Peritoneal cell population was obtained at day zero by washing the peritoneal cavity of Mice. Adherent cells were then separated using a 2 hrs. incubation in "Falcon" plates followed by washing. This macrophage-rich peritoneal cell population was found nonspecifically cytotoxic against 51Cr labeled tumoral target cells: P815 X DBA/2 mastocytoma cells, EL4 X C57BL/L lymphoma cells and spontaneous lymphoma AKR cells (same H--2k as CBA). This adherent peritoneal cell cytoxicity was demonstrated after 24 hrs. incubation with the target cells. It was found in nonspecific combination as well as when using target cells syngeneic to the donor. These findings suggest that adherent peritoneal cell cytotoxicity could be at least partly due to macrophages and result from factor (s) released by sensitized lymphocytes in vivo in the same way as has been previously demonstrated in vitro.

Animals↗
PubMed1978

Effect of thioglycollate on macrophage lysosomal enzymes.

Mice peritoneal macrophages obtained after i.p. injection of a medium containing thioglycollate (Institut Pasteur, Paris) have increased levels of beta glucuronidase and acid phosphatase, when compared with macrophages obtained without previous thioglycollate injection. The maximum increase is observed between 7 and 10 days after injection and reaches up to 3 to 4 times the normal activity. When using separately the various components of the medium, the same phenomenon may be observed but never to the same degree. The injection of thioglycollate also produces: a) an increase in total number of peritoneal cells, and b) an increase in the percentage of macrophages among these cells. Kinetic studies suggest that thioglycollate injection first induces an increase in the number of peritoneal macrophages and subsequently macrophage modifications resulting in lysosomal enzyme increase.

Acid Phosphatase↗
PubMed1977

Decrease of lysosomal enzymes in macrophages incubated with supernatants of mixed culture of allograft donor and recipient lymphocytes.

Incubation of mouse peritoneal macrophages (thioglycollate-induced) for 72 hours with the supernatant of a mixed lymphocyte culture (MLC) between skin allograft donor and recipient results in a decrease of macrophage acid phosphatase (EC 3.1.3.2.) and beta glucuronidase (EC 3.2.1.31). The alteration of these lysosomal enzymes is not explained by a loss of cell viability.

Acid Phosphatase↗
PubMed1977

[Automated analysis of proteins in the presence of Triton X-100].

The authors propose a method of autoanalysis of protein in presence of Triton X-100. This method uses Lowry's method in presence of sodium dodecyl-sulphate which permits inhibition of the formation of precipitates between Triton X-100 and Folin's reagent.

Albumins↗
PubMed1975

Macrophage arming factor release by allografted mouse lymphocytes stimulated by phytohermgglutinin.

Spleen cells from a C57BL/6 mouse allografted with DBA/2 skin may release a macrophage arming factor when stimulated with phytohemagglutinin. This in vitro nonspecific release is observed only when the recipient cells are collected during a limited period preceding or coinciding with graft rejection. The phenomenon disappears if the skin allograft has been removed before cell collection. It appears if an i.v. injection of donor cells is given to the recipient after graft removal, on the day preceding cell collection. These data suggest that this in vitro apparently nonspecific macrophage arming factor release by phytohemagglutinin-stimulated recipient cells may in fact disclose a previous specific in vivo immune cell triggering by graft antigens.

Animals↗
PubMed1975

Macrophage cytotoxicity in the mouse immune response against a skin allograft.

Macrophage-rich peritoneal cell populations from C57BL/6 mice grafted with DBA/2 skin were found to be cytotoxic against 51Cr-labeled target cells from the donor strain. Normal peritoneal macrophages were also rendered cytotoxic by incubation with acellular supernatants of mixed lymphocyte cultures (MLC) between an allograft recipient and a donor mouse. Supernatants alone were not cytotoxic. The macrophage arming factor(s) was found in supernatants when the MLC was performed after more than 6 to 9 days following grafting. In order to produce MAF, sensitized lymphocytes must usually be stimulated in a specific way by donor type cells. The armed macrophage cytotoxicity was, however, not found to be specific in these experiments.

Animals↗
PubMedDate not supplied

Characterization of thymic cell subpopulations involved in IL-1- or GM-CSF-induced IL-6 production.

IL-6 has been demonstrated by in vitro studies to be a cytokine involved in thymocyte activation We show herein that thymocytes cultured at high concentrations in the absence of comitogen respond to IL-1 and, to a lesser degree, to GM-CSF, by producing IL-6. This phenomenon disappears rapidly with decreasing cell densities, suggesting the involvement of a minor cellular component of the thymus which may be solely responsible for or cooperate in IL-6 production. We have analysed several thymic subpopulations for IL-6 production and show that accessory cells, and eventually their precursors, are the major if not exclusive, producers of this cytokine. Mature steroid-resistant thymocytes do not secrete IL-6. Production of IL-6 by total CD4-CD8- thymic cells is largely reduced by the depletion of mature accessory cells which express I-A and Mac-1 antigens. As shown previously, accessory cell precursors within the CD4-CD8- compartment are induced to differentiate into M phi and DC in response to IL-1 and GM-CSF. We provide evidence that this maturation is associated with IL-6 production. Thymic DC and phagocytic cells of the thymic reticulum (P-TR) in vitro produce high levels of IL-6 which are enhanced by GM-CSF or IL-1. These factors have a synergistic effect on IL-6 production by total thymocytes, and on CD4-CD8- cells that are not depleted for mature I-A+ Mac-1+ accessory cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Demonstration of a human lymphokine which renders macrophages cytotoxic.

Incubation of human peritoneal macrophages with cell free supernatants of mixed human lymphocyte cultures (MLC) renders them cytotoxic to labelled target tumour cells. The factor responsible for this effect is found as early as the second day of MLC. The production of this factor in man does not seem to require previous sensitization. In contrast with observations in mice, we have not yet demonstrated in man any clear-cut difference between the macrophage cytotoxicity index observed with supernatants from normal MLC and from MLC between the donor and the recipient of a skin allograft. Human blood monocytes can also be rendered cytotoxic by MLC acellular supernatants, but their cytotoxicity is neither as consistent nor as strong as with macrophages. This human factor does not render mouse macrophages cytotoxic.

Animals↗