Techniques were developed to isolate and purify guinea pig Kupffer cells (KC) so that their potential to interact with immunocompetent lymphocytes could be assessed. KC were prepared from guinea pig liver by sequential enzymatic digestion with collagenase and trypsin, followed by differential centrifugation, overnight culture, and glass adherence. Peritoneal exudate macrophages (PEM), induced with mineral oil but treated in otherwise identical fashion, were used for comparison in all experiments. More than 95% of the cells in KC preparations had the morphologic features of mononuclear phagocytes (Mø) and possessed peroxidase and nonspecific esterase activity. KC also exhibited many of the physiologic characteristics of Mø, including glass adherence, fluid phase pinocytosis, and phagocytosis of both nonspecific and opsonized particles. The capacity of KC to function as accessory cells necessary for the induction of mitogen-stimulated T lymphocyte proliferation was examined. Lymph node lymphocytes (LNL) depleted of adherent cells by passage over nylon wool columns were used as the responding T cell population. LNL when cultured alone were unable to undergo proliferative responses to optimal concentrations of phytomitogens. The addition of either KC or PEM to these cultures restored mitogen responsiveness to LNL. Furthermore, modification of both KC and PEM by treatment with neuraminidase and galactose oxidase generated mitogenic moieties capable of inducing blastogenesis in adherent cell-depleted LNL populations. These results provide evidence that KC are capable of functioning as accessory cells for the activation of T lymphocytes.
This research was supported by United States Public Health Service Grant 5 P01 AM19329 and Training Grant 5 T32 AM07100.