Foreign serum-induced bile duct lesion (BDL) in athymic BALB/c nude mice

To investigate a role of cellular immunity in foreign serum-induced bile duct lesion (BDL) in mice, athymic BALB/c nude (nu/nu) mice were intraperitoneally injected with swine serum (SS) twice a week up to 8 weeks and were compared with euthymic BALB/c heterozygote (nu/+) and wild-type (+/+) mice treated with SS in the same way for 4 weeks. All immunized nu/+ and +/+ mice developed marked BDL, and their sera showed high anti-SS IgE and IgG1 antibody titers, whereas no immunized nu/nu mice developed lesions, and their sera showed no elevation of antibody titers. Next, nu/nu mice were reconstituted with splenocytes derived from nu/+ mice, and then were intraperitoneally injected with SS twice a week for 3 weeks. Most of the reconstituted nu/nu mice developed BDL, and their sera showed the elevation of anti-SS IgE and IgG antibody titers. These results suggest that cellular immunity may play a pivotal role in the pathogenesis of swine serum-induced BDL.