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E Hem

Publications and source records attributed to E Hem.

46 records · Page 3Linked to original sources
PubMed1979

Modulation by macrophages of lymphocyte responses to phytohaemagglutinin, concanavalin A and semiallogeneic cells.

To investigate the effect of macrophages on rat lymphocyte activation by phytohaemagglutinin (PHA), concanavalin A (Con A) and semiallogeneic cells (uniderectional MLR), increasing concentrations of peritoneal cells (PC) were added to cultures of lymph node lymphocytes. Lymph node cell preparations contained 2-4% esterase positive cells (macrophages/monocytes). Any additional PC seemed only to inhibit MLR, whereas optimal responses of PHA and Con A stimulated cultures occurred when 1-2% abd 3-7% PC respectively were added. Ten percent PC markedly inhibited the response of both PHA and Con A stimulated cultures when added for the last 24 h of incubation. Inhibitory cells were shown to belong to the glass-wool adherent population of PC.

Animals↗
PubMed1978

Freezing of rat lymphocytes. V. The effect of suppressor cells in phytohaemagglutinin-stimulated spleen cell cultures before and after freeze-thawing.

Spleen lymphocyte proliferation, as measured by 3H-thymidine incorporation induced by phytohaemagglutinin (PHA), was increased after freeze-thawing with 10% dimethyl sulphoxide. Depletion or intoxication of macrophages in fresh spleen cell preparations also increased lymphocyte proliferation in response to PHA. On the other hand, freezing of macrophage-depleted spleen cell suspensions lowered 3H-thymidine uptake of stimulated cultures. At concntrations above 3%, macrophages added to cultures of fresh purified lymphocytes showed a dose-dependent inhibitory effect on the PHA response, and fresh macrophages were more inhibitory than frozen-thawed macrophages. Purified lymphocytes mixed with 10% macrophages showed a higher response after freeze-thawing. It is concluded that macrophages suppress the lymphoproliferative response to PHA in rat spleen cell cultures, and that these macrophages are more sensitive than lymphocytes to the present freeze-thaw process.

Animals↗
PubMed1977

Freezing of rat lymphocytes. IV. In vitro and in vivo responses of T-cells.

Rat lymph node lymphocytes have been frozen-thawed with 10% dimethyl sulphoxide as cryoprotectant. The present study shows that these cells respond well in T-cell functional assays, such as stimulation with phytohaemagglutinin, as responder cells in the mixed lymphocyte reaction and in the local graft-versus-host assay. The magnitude of the responses obtained with frozen-thawed cells was some 70-80% of corresponding fresh cells.

Animals↗
PubMed1976

Freezing of rat lymphocytes. III. Freezing of plaque-forming cells and restoration by frozen-thawed normal cells of antibody production in irradiated rats.

The present investigation is an extension of earlier work with dimethyl sulphoxide (DMSO) protected frozen-thawed rat lymphocytes. In the present work it is shown that some 85-90% of the haemolytic plaque-forming cells (PFC) survived the freeze-thaw process. Irradiated rats were restored with fresh and frozen-thawed cells and immunized against sheep red blood cells (SRBC). Evidence is presented that a restrictive control of the PFC response by suppressor cells present in the spleen cell suspension is lost during the freeze-thaw process, giving a higher number of PFC/spleen in recipients of frozen-thawed mixed spleen and lymph node cells than in rats receiving the corresponding fresh preparations.

Animals↗