J. Gen. Appl. Microbiol., 51, 125–131 (2005)

Human hepatitis B virus (HBV), the prototype of hepadnavirus family is a small-enveloped virus that replicates by reverse transcription within hepatocytes of an infected individual (Loeb and Ganem, 1993; Nassal and Schaller, 1993). It causes a variety of acute and chronic liver diseases including hepatocellular carcinoma (HCC) and cirrhosis in human and in other higher primates such as chimpanzees (Ganem and Varmus, 1987). The nucleocapsids of HBV contain 180 or 240 subunits of core protein, serologically known as core antigen (HBcAg) (Böttcher et al., 1997). HBcAg comprises 183 amino acid residues with a molecular weight of 22 kDa (Pasek et al., 1979). An outer envelope derived from the host cell membrane surrounds the viral capsid and embedded in the envelope are three distinct but related forms of surface antigen (HBsAg): S(small), M(middle) and L(large) HBsAg. Inside the viral nucleocapsid is the partially double stranded DNA genome of 3.2 kb which is covalently attached to the polymerase protein (P) (Ganem, 1991). The phage enzyme-linked immunosorbent assay (phage-ELISA) is a modified ELISA-based technique with the primary antibody replaced with the fusion phage. In the first method of this study, the bound phage is detected using monoclonal antibody (mAb) against the phage that is conjugated to horseradish Detection and precipitation of hepatitis B core antigen using a fusion bacteriophage