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Aim: To prepare monoclonal antibodies against HBsAg and estimate its binding capacity to both wild-type and varies of immune escape mutant-type HBsAg., Methods: Using self-made the anti-HBs G6 mAb and HRP-labeled goat anti-HBs antibody, A sandwich ELISA for detection both wild-type and varies of immune escape mutant-type HBsAg has been developed. Applying this assay, to detect 17 species of whole gene wild-type and recombination expressed HBsAg which varied in "a" determinant. to evaluate its clinical application characteristic of this assay, we used the other commercial reagents to Comparing with it., Results: One strain hybridoma cell lin secreted anti-HBs mAb (defined G6), was obtained. It grew stably and the titers of the culture supernatant and hydroperitoneum were 2 048 and 4 096x10(3). The sensitivity to the wild-type HBsAg of this assay was less than 0.125 microg/L. This anti-HBs mAb can bind with 12 in 15 species mutant HBsAg (P/N> or =2.5), and 2 of them were low absorbent value at 450 nm(A(450)) group which was 7.55 percent of the wild-type, 1 of them was middle A(450) value group which was 59.40 percent of the wild-type, 9 of them were high A(450) value group which was 92.1-109.4 percent of the wild-type. The low A(450) value group and the negative group were diversified in 120-124 basyl in I loop of the HBV "a" determinant. We also used other commercial reagents, which was widely used in clinic, to detect partial species mutant HBsAg, the average A(450) value was less than foregoing assay., Conclusion: The G6 anti-HBs mAb was able to bind most of the immune escape mutant HBsAg in the test. And there would be some special regulations between the mutant site and the recombination expressed HBsAg binding capability.

Objective: To search for and verify some common B cell epitopes in the core proteins of woodchuck hepatitis virus and human hepatitis B virus., Methods: Monoclonal antibodies against both core proteins of woodchuck hepatitis virus (WHV) and human hepatitis B virus (HBV) were prepared by inoculating Balb/c mice with denatured recombination WHV and HBV core proteins. ELISA and immunoblotting assays for WHcAg and HBcAg were carried out by using these antibodies. Immunohistochemistry was carried out with liver tissue sections of both WHV-infected woodchucks and chronic HBV-infected patients. The epitopes were mapped with the mouse mAbs (6D1 and 1H4) by using a panel of 24 16mer overlapping peptides covering the entire WHcAg. The amino acid sequences of WHcAg and HBcAg were compared., Results: Cross-reactions were observed between mAbs (6D1 and 1H4) and WHcAg and between Mabs and HBcAg/HBcAg in ELISA and immunoblotting assay. Liver tissue sections of both WHV-infected woodchucks and chronic HBV-infected patients could be stained specifically by mAbs. The epitopes were mapped at aa1-8 (6D1) and aa125-140 (1H4) of the core proteins of both WHV and HBV by using ELISA assay. WHcAg and HBcAg share similar amino acids sequences at aa1-8 and aa125-140 respectively., Conclusion: The core proteins of woodchuck hepatitis virus and human hepatitis B virus share common linear B cell epitopes which span aa1-8 and aa125-140 respectively.