MGQNLSTSNP LGFFPDHQLD PAFRANTANP DWDFNPNKDT WPDANKVGAG AFGLGFTPPH
GGLLGWSPQA QGILQTLPTN PPPASTNRQS GRQPTPLSPP LRNTHPQAMQ WNSTTFHQTL
QDPRVRGLYF PAGGSSSGTV NPVPTTVSPI SSIFSRIGDP TRILTIPQSL DSWWTSLNFL
GGTTVCLGQN SQSPTSNHSP TSCPPTCGYR WMCLMLPVCP LIPGSSTTTG PCRTCTTPAQ
GTMYPSCCCT KPSDGNCTCP IPSSWAFGKF LWEWASHHHH HH
Hepatitis B virus (HBV) is a small, enveloped virus belonging to the Hepadnaviridae family. It causes hepatitis B, a disease characterized by liver inflammation, damage, and an increased risk of hepatocellular carcinoma. The HBV genome consists of partially double-stranded circular DNA, which encodes several viral proteins, including the surface proteins (pre-S1, pre-S2, and HBsAg), the pre-core and core proteins (HBeAg and HBcAg), DNA polymerase, and the X protein .
The surface antigen of HBV, known as HBsAg, is a key marker for screening and monitoring HBV infection. HBsAg is a spherical envelope protein that surrounds the nucleocapsid (core antigen, HBcAg). It plays a crucial role in the virus’s ability to infect liver cells and is the primary target for the immune response against HBV .
HBV exhibits strain heterogeneity, leading to distinct subtypes characterized by antigenic determinants on the surface antigen (HBsAg) and their corresponding antibodies. All HBsAg specimens possess a common group determinant, known as “a.” However, there are two sets of subdeterminants, namely “d” or “y” and “w” or “r,” which are mutually exclusive or allelic. These subdeterminants are used to identify different subtypes. Based on the antigenic variations, HBsAg can be classified into at least four major groups: adw, ayw, adr, and ayr .
Recombinant HBsAg ayw is a genetically engineered version of the surface antigen. It is produced using recombinant DNA technology, where the gene encoding HBsAg is inserted into a host organism, such as yeast (Saccharomyces cerevisiae) or bacteria (Escherichia coli). The host organism then expresses the HBsAg protein, which can be purified and used for various applications, including vaccine production .
One specific recombinant HBsAg ayw variant involves a mutation at position 145, where the glycine residue is replaced with arginine (G-145-R). This mutation has important implications for the antigen’s behavior and immunogenicity. The recombinant HBV Surface Antigen (subtype ayw, mutation G-145-R) is widely used in the development and production of vaccines against hepatitis B .
Recombinant HBsAg ayw is crucial for the development of hepatitis B vaccines. Vaccination is one of the most effective strategies for preventing hepatitis B infection and its associated complications. The recombinant antigen is used to stimulate the immune system to produce antibodies against HBV, providing immunity to the virus. Additionally, recombinant HBsAg is used in diagnostic assays to detect HBV infection and monitor the effectiveness of vaccination .