Neutrophils will be isolated from normal human volunteers and placed in cell culture with isolated hepatocytes or C3A cells (hepatoblastoma cell line that exhibit many characteristics of normal hepatocytes). These experiments will evaluate the mechanisms by which neutrophil adhere to the surface of hepatocytes, and the mechanisms by which the attached neutrophils can damage or kill the hepatocytes. Mechanisms of adhesion will involve understanding of the chemokines released by the hepatocytes that stimulate neutrophil adhesiveness, the cytokines that activate hepatocytes to express chemokines and adhesion molecules, the adhesion receptors on the neutrophil surface that are able to recognize the adhesion molecules on the hepatocyte surface, and the ability of adhesion to enhance and focus cytotoxic chemicals coming from the stimulated neutrophils. In addition, the role endotoxin can play in these sequence of events is being studies, and the specific cytotoxic mechanisms released by the neutrophils are under study. As noted in the brief summary, this grant only supports use of human cells in vitro (i.e., all experiments will be done in tissue culture). The purpose of working with this experimental model is to define what mechanisms should in future experiments be evaluated in patients with endotoxin induced disease.

Only blood from normal subjects will be used in the in vitro experiments.