Stability of the recombinant hepatitis B core antigen

Area of Science:

• Biochemistry
• Immunology
• Molecular Biology

Background:

• Hepatitis B core antigen (HBcAg) is a key component of the hepatitis B virus.
• Understanding HBcAg stability is crucial for vaccine development and diagnostic assays.

Purpose of the Study:

• To characterize the stability and immunoreactivity of recombinant HBcAg under various physical and chemical conditions.
• To determine the impact of heat, pH, detergents, and proteases on HBcAg integrity.

Main Methods:

• Recombinant HBcAg was expressed and purified from Escherichia coli.
• Immunoreactivity was assessed using a paramagnetic particle-based enzyme immunoassay.
• Stability was tested against heat, pH variations, sodium dodecyl sulfate (SDS), ethanol, methanol, and proteolytic enzymes.

Main Results:

• Recombinant HBcAg retained immunoreactivity after heating at 70°C for 60 min but was inactivated at 85°C for 10 min.
• HBcAg was stable between pH 5 and 10.5, with inactivation at pH 2 and 13.5.
• SDS, ethanol, and methanol significantly reduced HBcAg reactivity. Papain and bacterial protease degraded HBcAg, while trypsin and chymotrypsin did not.
• Combined SDS and 2-mercaptoethanol caused initial loss, followed by partial recovery and eventual degradation.

Conclusions:

• Recombinant HBcAg exhibits defined stability limits concerning temperature, pH, and chemical treatments.
• These findings provide critical data for optimizing the use of recombinant HBcAg in diagnostic and potentially therapeutic applications.
• The differential sensitivity to proteases suggests specific structural features of HBcAg influencing its degradation pathways.