RES and immune suppression in traumatic shock.

Stimulation of reticuloendothelial function was previously shown to protect against the consequences of traumatic shock, but paradoxically RE stimulation appeared to decrease the number of antibody-forming cells that developed from immunization with heterologous erythrocytes. A decrease in the number of hemolytic plaque-forming cells (PFC) was absent in trauma-resistant animals, whereas an increased number of cells was produced by impairing the phagocytic activity of RE cells. In order to determine whether phagocytic or adherent cells from rat spleen cell preparations were suppressing the PFC response, macrophages were removed with a magnet after incubating with carbonyl iron powder for one hour. Control cultures were prepared with mixed spleen cells. The hemolytic plaque-forming capacity increased 50-fold from control mixed spleen cultures as compared to those from which spleen macrophages were removed. The addition of an equal number of adherent phagocytic cells to cultures of macrophage-depleted spleen cells prevented this increase. Macrophages present in the spleen appear to be responsible for this low PFC response in the rat and may suppress the antibody-forming cell response to TR rats.