Induction of autoimmune hepatitis and autoantibodies to liver antigens by neonatal thymectomy in mice

Abstract

SUMMARYWe examined development of autoimmune hepatitis in neonatally thymectomized C3H/HeN mice and tried to characterize the nature of liver antigens recognized by the autoantibodies at the molecular level. Autoantibodies to crude liver proteins detected by ELISA were found in 12 (67%) of 18 mice thymectomized 2 days after birth. However, autoantibodies were not detected in mice thymectomized 7 days after birth. The autoantibodies mainly consisted of IgG and reached the maximum level 8 weeks after birth. Hepatic inflammation, mononuclear cell infiltration in the portal area, was seen in 5 (28%) of 18 mice thymectomized 2 days after birth, but not in mice thymectomized 7 days after birth. Most infiltrating cells were Thy-1 lymphocytes. The serum autoantibody level to crude liver proteins in mice with hepatitis was much higher than that in mice without hepatitis. We fractionated crude liver proteins by a Sepharose 6B column and examined the reactivity against the autoantibodies. The autoantibodies of three of five mice with hepatitis reacted with the 150 kD liver proteins other than liver-specific protein (LSP). By Western immunoblotting of SDS-PAGE using LSP and fractionated liver proteins, we found that the molecular weights of the target antigens were 52 kD in LSP and 150 kD (strong band), 138, 128, 120 and 110 kD (weak band) in fractionated liver proteins other than LSP. This 150-kD target molecule in crude liver proteins was found only in liver. These results indicate that hepatitis and autoantibodies to liver proteins are induced spontaneously by neonatal thymectomy in mice, and the candidates of autoantigen in this hepatitis model are 52-kD protein in LSP and 150-kD liver proteins different from LSP. Still more, we regard the 150-kD molecule as a new autoantigen related to hepatitis.

DNA Vaccination Breaks Tolerance for a Neo-Self Antigen in Liver: A Transgenic Murine Model of Autoimmune Hepatitis

“…The expression of a neo-self Ag in this central immune organ led to negative selection of most high affinity/avidity self-reactive T cells. The fact that hepatitis can be induced by neonatal thymectomy in mice confirms the importance of T cell selection in this organ (6). Mouse models expressing IFN-␥ in the liver or deficient in TGF-␤1 have been reported to develop liver tissue injury, thereby showing the significance of regulatory cytokines in pathogenesis of cytolysis (7,8).…”

Human T cell responses to recombinant mite antigens of Dermatophagoides farinae

“…The total IgE level in allergic sera was detected by sandwich ELISA [26]. Flat-bottomed microtitre plate (Sumitomo Bakelite, Tokyo, Japan) was coated at 37ЊC for 2 h or overnight at 4ЊC with sheep anti-mouse IgE antibody (5 mg/ml; The Binding Site, Birmingham, UK), followed by blocking with 1% bovine serum albumin (BSA; Sigma, St Louis, MO) in PBS.…”

Cytotoxic Effect of an Anti-Liver Monoclonal Autoantibody obtained after Neonatal Thymectomy in Mice

“…Mice were thymectomized 2 days after birth as previously described [10]. In brief, mice were anaesthetized with ether.…”

“…ELISA was performed using the method previously described [10]. Briefly, microtitre plates (Sumitomo Bakelite Co., Tokyo, Japan) were coated at 4°C overnight with crude liver protein or LSP (50 g/ml).…”

“…The characterization of liver autoantigens to induce autoimmune hepatitis in neonatally thymectomized mice, therefore, has not been extensively analyzed. In a previous paper, we successfully induced autoimmune hepatitis and autoantibodies reactive with liver antigens by neonatal thymectomy in C3H/HeN mice, and analyzed the nature of the liver antigens recognized by this autoantibody [10,11]. In order to characterize further the nature of liver antigens using autoantibodies, the monoclonal antibody technique will be useful.…”