The study on the chronicity of experimental autoimmune hepatitis in neonatally thymectomized mice

Using an autoimmune hepatitis model of A/J mice which was prepared with immunization of syngeneic liver proteins, we observed influence of neonatal thymectomy on the chronicity of hepatitis. Hepatitis was severer in neonatally thymectomized mice (group B) than in non-thymectomized controls (group A). 3 months after the final immunization, piecemeal necrosis was recognized with high frequency in group B but it was not recognized in group A. The level of autoantibody to liverspecific lipoprotein (LSP) was higher in group B than group A, and high level of that in group B continued unchangeably until 3 months after the final immunization. Production of the autoantibody to LSP was reduced by adoptive transfer of normal mouse spleen cells, but the spleen cells of neonatally thymectomized mice showed no such effects. This experiment suggests that neonatal thymectomy is apt to abolish tolerance to LSP on account of depressed suppressor activity to autoantigen, and accordingly hepatitis is increased and continues.