Effect of benzene and its metabolites on natural killer activity of mouse spleen cells in vitro.

The effects of benzene and its metabolites, phenol and hydroquinone, on natural killer (NK) activity in mouse spleen cells in vitro were studied. NK activity was evaluated by the specific release percentage of 51Cr from labeled YAC-1 cells after YAC-1 cells (target cells) were incubated with spleen cells (effector cells) of mice at ratios of effector cells to target cells (E/T) of 100/1, 50/1, and 25/1. Benzene was shown to inhibit NK activity at concentrations of 1 x 10(-5) M-5 x 10(-5) M, phenol at concentrations of 1 x 10(-7)-5 x 10(-5) M and hydroquinone at concentrations of 1 x 10(-6) M-1 x 10(5) M. Phenol and hydroquinone depressed NK activity in a dose-dependent manner. This study demonstrated that NK cell function of mouse spleen was depressed by exposure to benzene and its metabolites in vitro. Hydroquinone and phenol have very potent toxicity for suppression of immunosurveillance.