May regulate immune response to the intracellular capsid in acting as a T-cell tolerogen, by having an immunoregulatory effect which prevents destruction of infected cells by cytotoxic T-cells. This immune regulation may predispose to chronicity during perinatal infections and prevent severe liver injury during adult infections. Homodimerizes. Phosphorylated. Cleaved by host furin. Belongs to the orthohepadnavirus precore antigen family.