title: Definitive evidence that natural killer (NK) cells inhibit experimental tumor metastases in vivo.
abstract: Effector lymphoid cells that inhibit hematogenous tumor metastasis in normal unimmunized mice were studied. Mice pretreated with cyclophosphamide (Cy) exhibited a diminished ability to destroy circulating tumor cells, which, in turn, caused an increased incidence of experimental pulmonary metastasis. Adoptive transfer of spleen cells from unimmunized syngeneic donors abrogated the Cy-induced enhancement of metastasis formation. The effector cell active in these adoptive transfer experiments was sensitive to treatment with specific anti-NK-1.2 antibodies and complement. This treatment was shown by in vitro tests to deplete or inactivate NK cells selectively. These findings provide direct evidence that NK cells play a significant role in the inhibition of hematogenous tumor metastases in vivo.
mesh_terms: D000818:Animals; D000906:Antibodies; D003520:Cyclophosphamide / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic; D007111:Immunity, Cellular; D008214:Lymphocytes / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008934:Mitogens / Q000494:pharmacology; D009362:Neoplasm Metastasis; D013154:Spleen / Q000276:immunology
chemical_list: D000906:Antibodies; D008934:Mitogens; D003520:Cyclophosphamide