A novel hepatitis B virus mutant with A-to-G at nt551 in the surface antigen gene

Table 1 Detection of immunoreactivity of the expressed HBsAgs to anti-'a' monoclonal antibodies by radioimmunoassay^a

Anti-'a'monoclonal antibodies	Wild-type HBs (133Met)	Mutant HBs (133Val)
A6	1118 (5.82)	774 (3.93)
A11	932 (4.80)	744 (3.76)
S17	945 (4.87)	630 (3.14)

^aCounter per minute (cpm), the number in the parentheses is P/N value. According to the solid RIA kit producer's recommendation, P/N = (sample cpm-background)/(negative control cpm-background). Untransfected cells were used as negative control, average cpm was 240. Blank polystyrene beads were used as background, average cpm was 58. P/N ≥ 2.10 is considered to be positive reactivity. The more the P/N value, the stronger the reactivity.

Table 2 Immunoreactivity of vaccine-raised human anti-HBs to ricombinant wild-type HBsAg and to recombinant mutant HBsAg in an ELISA assay

Plate coated with	Wild-type rHBsAg				Mutant rHBsAg				Control
Vaccine-raised anti-HBs	1:1	1:2	1:4	1:8	1:1	1:2	1:4	1:8	1:1
Absorbance at 490 nm	2.45	1.32	0.71	0.28	0.53	0.28	0.15	0.06	0.04