Quantification of HBsAg: Basic virology for clinical practice

Figure 1 Schematic model of hepatitis B surface antigen structure. Three forms of hepatitis B surface (HBs) antigen (Dane particle, filamentous particle, and spherical particle) are visualized in serum by electron microscopy. These are composed of small, middle, and large hepatitis B surface proteins. LHBs: Large HBs proteins; MHBs: Middle HBs proteins; SHBs: Small HBs proteins.

Figure 2 Schematic presentation of the S/preS1/preS2 gene, RNA transcripts, and translational products. Opening reading frame S has three internal AUG codons. Transcription to produce the 2.1 kb and 2.4 kb mRNAs first occurs after translation into small hepatitis B surface proteins (SHBs), middle hepatitis B surface proteins (MHBs), and large hepatitis B surface proteins (LHBs) ensues with different promoters.