hepatitis B surface antigen + adjuvant 1

This is a **combination vaccine formulation** consisting of hepatitis B surface antigen (HBsAg) and an **adjuvant** referred to as "adjuvant 1." The HBsAg is usually composed of S, pre-S1, and pre-S2 proteins, often forming virus-like particles (VLPs) or subunit particles. The addition of a novel adjuvant, such as L-pampo (a lipopeptide plus synthetic dsRNA that activates TLR2 and TLR3) or PEG–PAEEP (a cationic polyphosphoester-based polymer), is designed to enhance the immune response versus conventional alum adjuvants. These formulations aim to induce stronger and broader antibody responses, including shifts in antibody isotypes (e.g., increased IgG2a or IgG2b) and a more potent Th1-oriented immunity. Advanced adjuvants are intended to improve antibody titers, speed of seroconversion, antigen-dose sparing, and long-term protection against hepatitis B virus infection[1][2].