Tetrabromobisphenol A activates mitogen‐activated protein kinases in human natural killer cells

Tetrabromobisphenol A (TBBPA) is used both as a reactive and an additive flame retardant in a variety of materials and contaminates the environment. Humans are exposed to TBBPA by inhalation, dermal contact, and ingestion and it has been found in human blood samples. Human natural killer (NK) lymphocytes are critical in immune defense against viral infection and tumor development by killing (lysing) virally infected and tumor cells. The lytic function of NK cells involves the activation of mitogen activated protein kinases (MAPKs). Previously, we have shown that exposure to 10‐0.5 μM TBBPA decreased the lytic function of NK cells. In this study we examined the effects of concentrations of TBBPA that inhibited lytic function on the phosphorylation state and total levels of the MAPKS, p44/42, p38, and JNK. Results indicate that exposure of human NK cells to 10‐0.5 μM TBBPA for 10 minutes increases the phosphorylation (activation) of MAPKs. This TBBPA‐induced phosphorylation of MAPKs may leave them unavailable for activation by virally infected or tumor target cells and thus contribute to the observed decreases in lytic function seen in NK cells exposed to TBBPA. Supported by NIH grant S06 GM008092‐35