Immunologic effects of nickel. II. Suppression of natural killer cell activity.

A single intramuscular injection of nickel chloride (18.3 mg/kg) caused a significant reduction in murine splenic natural killer (NK) cell activity. This reduction in NK activity was not associated with a significant reduction in spleen cellularity nor in the production of suppressor cells. In a 4-hr 51Cr-release assay, NK cell activity was suppressed in both CBA/J and C57BL/6J mice. Administration of the nickel dose (i.e., 18.3 mg/kg total) over a 2-week period also caused a significant reduction in NK cell activity. In an in vivo NK assay, the clearance of [125I]iododeoxyuridine-labeled YAC-1 tumor cells from the lungs of nickel-treated mice was significantly reduced compared with saline injected controls. Another in vivo correlate of nickel-induced NK suppression was observed in mice injected with the B16-F10 melanoma. Mice given a single intramuscular injection of NiCl2 (18.3 mg/kg) developed significantly greater numbers of lung tumors than saline controls. The results indicate that NiCl2 is a potent suppressor of NK cell activity.