A new rapid method is described for the isolation and purification of functional active human Kupffer cells without the need of in situ perfusion techniques. Liver wedge biopsies (3 to 5 g), obtained after laparotomy, were incubated with pronase under continuous pH registration. Human Kupffer cells were subsequently separated from other nonparenchymal cells by Nycodenz gradient centrifugation and purified by counterflow centrifugal elutriation. Kupffer cells, 1.7 ? 0.4 X lo6 per gram liver, were isolated with a purity of 95% ? 3%. Cell-mediated cytotoxicity of Kupffer cells was assayed against a human colon carcinoma cell line (SW948). Kupffer cell cytotoxicity was 42% i 9% (mean ? SD) at an effectorto-target cell ratio of 10 and significantly increased to 73 2 17% (P < .05) after activation of Kupffer cells with interferon-gamma. In conclusion, a reliable and relatively simple method is provided to isolate and purify fresh human Kupffer cells in large yields, which show spontaneous as well as gamma-interferon-induced cyto- toxicity against a human colon carcinoma cell line. (HEP-ATOLOGY 1995;21:740-745.)
The liver is the major site of metastatic growth of primary colorectal cancer in humans, which occurs as a result of tumor cells being released into the blood or lymphatic circulations. Macrophages are implicated as playing an important role in host defense against primary and metastatic neop1asia.l.' Because the liver is the largest reticuloendothelial organ in the body, liver macrophages, the so-called Kupffer cells, could be potential effector cells for immunomodulation to control tumor cell g r ~w t h . ~ However, most knowledge of antitumor activities of Kupffer cells is based on experimental animal ~t u d i e s . ~. ~ Abhreviations: TNF, tumor necrosis factor; IFN, interferon; GBSS, Gey's balanced salt solution; Em, effector-to-target cell ratios.