Fig. 7.

IL-21-induced or IL-33-induced clearance of BPS persistence engenders protection from re-challenge. HDI mice harbouring BPS persistence were treated with injections of plasmids expressing IL-21 (a) or IL-33 (b) at 4 and 7 w.p.i. and those displaying at least 4 weeks of sustained HBsAg negativity (see Fig. 6) were re-challenged in the same way as initial BPS HDI. BPS HDI mice treated with vector control were used as control and re-challenged similarly (c). Sera were collected at indicated time points and levels of HBsAg (left), HBsAb (middle) and HBeAg (right) were analysed using ELISA. Dotted lines represent cut-off thresholds. w.p.i. weeks post injection of BPS re-challenge