The ability of lymphokine and lipopolysaccharide to induce procoagulant activity in mouse macrophage cell lines.

A comparison was made of the abilities of mouse macrophage cell lines and cultured bone marrow-derived macrophages to respond to lymphokine and lipopolysaccharide (LPS) in the macrophage procoagulant assay (MPCA). Mouse macrophage cell lines PU5 and WEHI 265 responded to low concentrations of lymphokine and LPS by increased procoagulant activity; the activity of PU5 cells was comparable to that of TG-PEC. Approximately one-half of the MPCA induced by lymphokine after 20 hr culture was detectable after 2 hr with either cell line. J774 was unresponsive to LPS but responded weakly to lymphokine, and P388D1 and WEHI 274 were unresponsive to both stimuli as determined by the MPCA test. Addition of purified T cells (five T cells to one macrophage) to the unresponsive cell lines induced procoagulant activity in the presence of either stimulus, which suggests that cell contact is necessary in some cases. Only J774 cells responded to lymphocyte-derived chemotactic factor (LDCF) or endotoxin-activated mouse serum (EAMS) in chemotaxis assays. Immature bone marrow cells responded to chemotactic stimuli, and procoagulant activity was induced with lymphokine after 4 days in culture. Cells cultured for 7 days had about twice as much MPCA, but further culturing did not result in cells with enhanced activity. The procoagulant responsiveness of different macrophage cell lines to lymphokine or LPS may reflect differences in the maturation and differentiation states of these cells.