using PMA alone (grey bars) and in combination with calcium ionophore (CaI 955 μM, black bars). (D) TCR-/- deficient cells responded to PMA (162 nM) by up-regulating AP-1 activity. Statistical significance from the control was determined using Student's t-test. (n = 4). Controls were arbitrarily set to 1.   NF-κB levels showed a transient increase at 1 min after exposure to PMA (figure 2a). However, 1 h after exposure the NF-κB levels began to drop reaching the lowest levels by 6 h, after which they increased again by 24 h. Exposure of Jurkat T-cells to HK E. coli resulted in a dose-depen