Detection of Hepatitis B Virus DNA in Human Serum by Dot Hybridization Using a Biotin-Labelled Probe(*)

A dot blot hybridization technique utilizing a biotin-labelled recombinant DNA probe was used to examine hepatitis B virus (HBV) DNA in serum. The lowest amount of HBV DNA in serum detectable by the color development of an avidin-biotin alkaline phosphatase complex was 40 picogram per 50 microliter. Validity of this method was confirmed by autoradiography using (32)P-labelled and (3)H-labelled HBV DNA probes. HBV DNA was found in 100% (34/34) of the HBsAg-positive and in 73.5% (25/34) of the HBsAg-negative subjects. In contrast, all nine cases showing negativity in HBV DNA were also HBsAg-negative. Correlation of HBe antigen/antibody with HBV DNA was investigated in 19 sera of which HBsAg was negative but anti-HBc-positive. Of 13 sera with anti-HBe 10 (76.9%) cases revealed HBV DNA positivity, while four (66.7%) of six sera without anti-HBe were positive in HBV DNA. In conclusion, serum dot hybridization assay utilizing a biotinylated probe proved useful in the detection of a free form of HBV DNA regardless of the presence of HBsAg and irrespective of HBeAg/anti-HBe status. Moreover, it is emphasized that practical advantages in speed, reproducibility, and safety have made this alternative even more attractive than autoradiography using radioisotope-labelled probes.