Kupffer cells are sessile tissue macrophages that have a role in liver defense against endogenous endotoxins. Because little information is available on the role of bovine Kupffer cells, we developed a primary culture method to investigate the function of bovine Kupffer cells. Kupffer cells were isolated from the caudate lobe of calf liver by perfusion with collagenase and pronase. Then, the cells were purified by gradient centrifugation followed by counterflow centrifugal elutriation. With the methods, a mean number of 1.5 x 10(6) Kupffer cells with a final viability of over 98% was obtained from 1 g of the liver. Over 95% of the isolated cells were positive for non-specific esterase activity and had surface molecule of CD68. The cultured Kupffer cells expressed mRNAs of tumor necrosis factor-alpha, interleukin (IL)-1 alpha, IL-1 beta and IL-6 by stimulation for 3 h with lipopolysaccharide. The primary culture of bovine Kupffer cells could be useful to investigate the systemic inflammatory response in bovine liver.