Vaccination with recombinant HBsAg–HBIG complex in healthy adults

A therapeutic vaccine for viral hepatitis B composed of yeast-derived recombinant HBsAg complexed to human anti-HBs immunoglobulin (yeast-derived-immunogenic complex, YIC) with alum as the adjuvant was evaluated for safety. In stage 1, 22 healthy Chinese adult volunteers were vaccinated with three doses of 30 μg, 60 μg or 90 μg of HBsAg in YIC at 4-week intervals. In stage 2, nine volunteers received 90 μg of HBsAg in YIC for six injections. All immunizations were well tolerated. Renal, liver function and other blood chemistry tests remained within normal range. All recipients developed serum anti-HBs, the highest being 1000 mIU/ml, and the subtypes of anti-HBs were IgG1 and IgG3. The serum levels of interferon-gamma (IFN-γ) and interleukin-2 (IL-2) were increased, while no significant increase was observed in interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-10 (IL-10) or tumor necrosis factor-alpha (TNF-α). These results indicate that this complex is safe and can induce a potent anti-HBs response.