FIG. 6.

RIA quantitation of HBsAg levels in the supernatants of PLC/PRF/5 cells cultured with human monoclonal anti-HBs IgG. During the first period (open bars), the cells were cultured in the presence of medium with FCS and two concentrations of anti-HBs. In parallel, cells were cultured with medium plus FCS only, i.e., without human IgG (FCS) or with nonimmune human IgG (ABS), as controls. After 2 days of culture, the supernatants were collected, and the same cells were maintained in culture for a further two intervals of 2 days each (shaded and solid bars, respectively) in medium with FCS without human IgG. The HBsAg levels in the supernatants were tested at the end of each period, i.e., at three time points. The bars represent the means and standard deviations of two separate experiments, with each experimental condition run in duplicate.