Fig 5. Reactivity of the wild-type HBsAg in a commercial ELISA assay and against an anti-tag mAb.
All the mutants of W3S and wild-type HBsAgs (W1S and W3S) were expressed by transient transfection in HEK 293-T cells. The culture supernatants and the cells were collected 72 h after transfection. (A and B) Reactivity of the wild-type and mtHBsAg from culture supernatants and cell lysates on a commercial ELISA kit. (C and D) Detection and reactivity of the wild-type and mtHBsAg from PEG-precipitated culture supernatants and cell lysates against an anti-Xpress mAb. The reactivity of HBsAgs was presented as the percentage of the OD450-630 of samples compared to W1S in all cases (A, B, C and D). The OD values of HBsAg ELISA and anti-tag reactivity (except W1S N146G from the culture supernatant) were normalized by the ratios of densitometric intensity of Western blotting compared to W1S, except W1S Q129R/G145R from the supernatants, since this mutant exhibited a remarkable loss in secretion ability (Fig 4A). Non-transfected cells served as negative control (NC). The mean value of three independent experiments is shown as the final reactivity of HBsAg. Error bars are shown as the standard errors of means (SEM). wt: wild-type; mt: mutant.