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M Dy

Publications and source records attributed to M Dy.

114 records · Page 7Linked to original sources
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Increased release of lymphokines by allografted mouse spleen cells following concanavalin A stimulation.

Using a test proposed in this laboratory for following macrophage "activation" (intracellular beta-glucuronidase content) and quantitative dilution studies, we have shown that lymphocytes from mice presensitized by a skin allograft release far more macrophage activating lympholines than do normal lymphocytes when non-specifically stimulated by concanavalin A. This difference may be due to latent metabolic changes of sensitized lymphocytes, but it may also express a modified balance among the various lymphocyte subpopulations within the spleen of grafted mice.

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PubMedDate not supplied

Role of macrophage activation in allograft immunity: in vivo studies.

Macrophage-rich adherent peritoneal cells from mice sensitized by two i.p. injections of allogeneic cells at days -- 12 and --2, were found non-specifically cytotoxic against (a) tumoral target cells, as evaluated by the chromium release test, and (b) normal target cells, as evaluated by a functional test based on the insulin secretion response to glucose stimulation of isolated pancreatic islet cells. This non-specific cytotoxicity was identical to that of macrophages "activated" by an in vitro incubation with supernatants of MLC between allograft donor and recipient as reported elsewhere. Moreover this cytotoxicity was not abolished by anti-theta serum treatment of adherent peritoneal cells before contact with target cells. It is concluded that an in vivo macrophage activation was obtained in our experiment. Using this same model, we found that the survival time of skin grafts from male C57BL/6 to female C57BL/6 mice was shortened if the graft was performed at the time when the recipient macrophages were found non-specifically cytotoxic (two days after the second allogeneic cell injection). The role of macrophage cytotoxicity in this accelerated allograft rejection is suggested by (a) the lack of any detectable cross-histocompatibility antigens between the immunizing cells and the skin graft, and (b) the absence of any alteration of the graft survival if the second immunizing injection two days prior to grafting is omitted (in that case only lymphocytes are found specifically cytotoxic against the strain of injected cells, while the non-specific cytotoxicity of macrophages is lacking).

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PubMedDate not supplied

Role of interleukin-2 receptors in the suppressive effect of spleen cells from anti-CD3-treated mice.

In the present study, we demonstrate that unresponsive spleen T cells from mice injected with a low dose of anti-CD3 mAb (single 10 micrograms i.v. injection) significantly inhibit Con A-induced proliferation of normal spleen cells. The induction of this phenomenon requires in vivo activation since spleen cells from mice injected with the F(ab')2 fragment of anti-CD3 mAb fail to promote it. Suppression of normal T cell proliferation is concomitant with increased expression of IL-2 receptor on spleen cells from anti-CD3-treated mice. It disappears within 3 days when IL-2R has returned to background levels. A normal proliferative response to Con A can be restored when high concentrations of IL-2 are added together with the "suppressor" cells. Taken together, these data support the notion that activated spleen cells from anti-CD3-injected mice exert their inhibitory effect by competing for the IL-2 generated during culture.

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