Anti-4-1BB monoclonal antibodies attenuate concanavalin A-induced immune-mediated liver injury in mice

Effective therapies for the treatment of immune-mediated liver disease are currently lacking. As a member of the tumor necrosis factor receptor superfamily, 4-1BB has a key role in T-cell activation and has been implicated in the development of autoimmune disorders. The purpose of the present study was to evaluate the potential therapeutic or preventive function of an anti-4-1BB monoclonal antibody (mAb) in a mouse model of concanavalin (Con) A-induced immune-mediated liver injury. A mouse model of immune-mediated liver injury was established by tail vein injection of Con A (20 mg/kg). 4-1BB mAb (100 µg), with or without methylprednisolone (MEP; 3 mg/kg), was intraperitoneally injected into the tail vein 2 h prior to or 2 h following Con A injection. Con A induced marked hepatocyte necrosis, significantly reduced CD 4(+)/CD25(+) T-cell levels, and increased the serum levels of aspartate transaminase (AST) and alanine transaminase (ALT), in addition to the percentage of 4-1BB(+) T-cells, compared with the control (all P<0.05). The administration of 4-1BB mAb prior to or following Con A injection was able to attenuate Con A-induced liver tissue damage and significantly reduce serum AST and ALT levels (P<0.05). A combination of MEP and 4-1BB mAb further reduced serum AST and ALT levels, compared with either treatment alone. In addition, administration of 4-1BB mAb and MEP alone or in combination significantly increased CD4(+)/CD25(+) T-cell levels, compared with the control (P<0.05). These results suggested that 4-1BB mAb was able to attenuate liver injury and preserve liver function in a mouse model of Con A-induced immune-mediated liver injury by promoting the expansion of CD4(+)/CD25(+) T-cells. Furthermore, a combination of 4-1BB mAb with MEP was associated with greater beneficial effects than either treatment alone. The clinical significance of 4-1BB mAb in immune-mediated liver disease remains to be elucidated in future studies.