[Liver regeneration and the immune system. 1. In vitro and in vivo activation of lymphocytes by liver regeneration].

When syngeneic lymphocytes and mitomycin C (MMC) treated regenerating liver cells prepared from a partial hepatectomized mice are cultured together, the in vitro DNA synthetic response is activated (sMLHLR: syngeneic mixed hepatectomized liver cell-lymphocyte culture). Ia+ Kupffer cells play an important role as stimulators in the responses, since the stimulating activity of regenerating liver cells is lost by the pretreatment of them with anti-Ia monoclonal antibody plus complement or the removing Kupffer cells from them. The lymphocytes are activated also in vivo during liver regeneration after a partial hepatectomy. Because, when lymphocytes prepared from hepatectomized mice are cultured with regenerating liver cells, lymphocytes are stimulated to accelerate their DNA synthesis in a typical manner of the secondary immune responses (secondary sMLHLR). In primary sMLHLR, the responder cells are mainly Lyt-1+ whereas in secondary sMLHLR they are mainly Lyt-2+. The mechanism of changing the Lyt phenotype of major responder cells from Lyt-1 to Lyt-2 during sMLHLR is discussed.