PASSIVE-IMMUNIZATION OF MICE AGAINST D-FACTOR BLOCKS LETHALITY AND CYTOKINE RELEASE DURING ENDOTOXEMIA

D factor, also known as leukemia inhibitory factor, is a pleiotropic c ytokine whose role during acute injury and inflammation is not known. Intraperitoneal administration of Escherichia coli endotoxin induced D factor gene expression in mice, and passive immunization against D fa ctor protected them from the lethal effects of endotoxin and blocked e ndotoxin-induced increases in serum levels of interleukin 1 and 6. Pea k levels of tumor necrosis factor and interferon gamma were not affect ed. These results indicate that D factor is an essential early mediato r of the inflammatory cytokine response and therefore may be important in the pathogenesis of the many inflammatory conditions, such as seps is, arthritis, allograft rejection, and cancer immunotherapy.