Borrego , F . , Lopez - Beltran , A . , Pena , J . , Solana , R . 1994 . Downregulation of Fc gamma receptor IIIA alpha ( CD 16 - II ) on natural killer cells induced by anti - CD 16 mAb is independent of protein tyrosine kinases and protein kinase C . Cell Immunol 158 , 208 - 217 .