The augmentation of lymphokine-activated killer cells induced by partial hepatectomy in mice

Spleen cells that are cultured with interleukin 2 for as short a time as 4 days develop the ability to lyse syngeneic natural killer-resistant tumor cells but not to lyse syngeneic lymphoblasts. When mice were subjected to partial hepatectomy (HEP), the spleen cells exhibited not only an augmentation of natural killer activity, but also an augmentation of in vitro induction of lymphokine activated killer (LAK) cells. Furthermore, the LAK cells exhibited lytic activities against syngeneic lectin-induced lymphoblasts and regenerating liver cells. The sensitivity of regenerating liver cells to lysis by LAK cells was detected as early as one day after HEP, and continued until day 14. Analysis by cell depletion techniques using monoclonal antibodies and complement, as well as discontinuous gradient sedimentation, indicated that the LAK cells activated by HEP were Thy-1+, Lyt-2+, asialo GM1+ and Lyt-1-, lymphocytes with a low density. After the intravenous (i.v.) administration of anti-asialo GM1 before HEP, the in vitro induction of LAK cells was remarkably inhibited.