Class I capsid assembly modulators induce potent anti-HBV activity through direct viral suppression, innate immune activation and caspase-3-independent clearance of infected hepatocytes.

Abstract

Capsid assembly modulators (CAMs) are promising antiviral agents for chronic hepatitis B virus (HBV) infection. This study investigates the anti-HBV activity and immunomodulatory effects of Class I CAMs (CAM-A) in vitro and in vivo. In HepAD38 cells, CAM-A treatment significantly upregulated the expression of interferon-stimulated genes (IP-10, MX1, OAS1). In AAV-HBV mice, CAM-A (GLS4) induced rapid reductions in HBV DNA and delayed HBsAg decline accompanied by transient ALT elevation, upregulated interferons and Tnfsf10/Tnfrsf10b gene expression, while terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and immunohistochemistry (IHC) experiments indicated caspase-3-independent cell death in HBV-infected hepatocytes. Importantly, the antiviral and HBsAg-lowering effects of CAM-A did not require adaptive immunity. Furthermore, combination of CAM-A with a TLR7 agonist in AAV-HBV mice, or with Peg-IFN-α in primary human hepatocytes (PHH) resulted in synergistic antiviral effects, underscoring the therapeutic potential of these agents to promote sustained HBsAg decline and support functional cure strategies in chronic HBV infection.