ANTIMETASTATIC EFFECT OF NK1(-CELLS ON EXPERIMENTAL HEMATOGENOUS TUMOR-METASTASES IN THE LIVER AND LUNGS OF MICE() T)

Depletion of both natural killer 1.1(+) (NK1(+)) intermediate alpha be ta T-cell receptor (int T) cells and NK cells by in vivo treatment wit h anti-NK1 antibody greatly increased hepatic metastases of intravenou sly injected EL4 cells as well as pulmonary metastases of 3LL cells in C57BL/6 mice. However, depletion of NK cells alone by anti-asialo GM1 (AGM1) antibody treatment did not increase the metastases in either o rgan. Interleukin-12 (IL-12) administration into mice induced strong c ytotoxicities of NK cell-depleted liver and lung mononuclear cells (MN C) comparable to those without NK-cell depletion and inhibited metasta ses in either organ. In contrast, in both NK cell- and NK1(+) int T-ce ll-depleted mice, IL-12 could not induce cytotoxic activity of liver a nd lung MNC and metastases in both organs increased with or without IL -12 treatment. These results confirmed the fact that NK1(+) int T cell s are more potent antitumour effecters than NK cells against experimen tal haematogenous tumour metastases.