Recombinant CHO-K1 cell transfected with empty expression vector containing the hygromycin resistance gene._x000D_This cell line serves as a negative control for:_x000D_ TCR Activator - CHO Recombinant Cell line, #60539; DAT CHOK1 Recombinant Cell Line, #60558; and NET - CHOK1 Recombinant Cell , #60557