ELISA genotyping of hepatitis B virus in China with antibodies specific for genotypes B and C

Hepatitis B virus (HBV) causes hepatitis B (HB) and distinct HBV genotypes can lead to different prognoses. However, HBV genotyping is rarely done in clinics, because the traditional method by PCR-based DNA sequencing is impractical for clinical diagnosis with tedious process and low success rate. Herein, we have established an ELISA-based genotyping method to quickly determine the HBV genotypes of HB patients in China. First, two commercial antibodies, 16D12 and 6H3 specific for HBV genotypes B and C respectively, are chosen as capture antibodies, since these two genotypes dominate in China. Then two home-made genotype-specific antibodies, B19 and C04, are used as the detection antibodies for genotypes B and C in sandwiched ELISA. The ELISA kit shows high sensitivity (> 95%) and specificity (> 95%) in detecting genotypes B and C of Chinese HB patients. Moreover, the ELISA kit has demonstrated higher success rate (98.7%) than PCR-based DNA sequencing (93.5%) and a commercial PCR-based genotyping kit (92.2%) for sera with HBV DNA ≥ 1000 IU/mL and HBsAg ≥ 250 IU/mL. Such an advantage is more obvious for the sera with HBV DNA < 1000 IU/mL. The kappa analysis between the ELISA and PCR-based DNA sequencing results exhibits a kappa of 0.836, indicating a good correlation.