Female SJL/J mice were obtained from Jackson Laboratories (Bar Harbor, ME) and all procedures conducted according to the principles outlined in the Guidelines of the Committee on Care and Use of Laboratory Animals. In the first set of experiments, mice were immunized at 12 weeks of age with a single 200 ml intraperitoneal injection of 500 mg of either bovine PDC-E2 or a-casein emulsified in complete Freund's adjuvant as described (Jones et al., 2000) ; the complete Freund's adjuvant (CFA) used contained 10 mg/ml Mycobacterium tuberculosis strain H37Ra (Difco) in incomplete Freund's adjuvant purchased from Sigma Inc. (St Louis, MO). In subgroups of mice, 3000 units of murine recombinant IFN-g was administered intraperitoneally twice a week for four weeks (Kyuwa et al., 1998) . The mice were divided into the following groups: (A) PDC-E2; (B) PDC-E2 and IFNg; (C) a-casein; and (D) a-casein and IFN-g in groups of 8 -12 animals (Table I) . Mice were serially observed and by 30 weeks of age, mice were sacrificed. This time period was chosen based on earlier observations by Jones et al. (2000) . Sera were assayed for autoantibodies. In addition, the liver, salivary gland, thymus, lung, heart, kidney, spleen, stomach, small and large intestine, were all removed for evaluation. Tissue specimens were fixed with 10% neutral buffered formalin and embedded in paraffin. Deparaffinized thin sections from each paraffin block were stained with hematoxylin and eosin for histology. Because some pilot data suggested the possibility of amyloid deposition, a Direct Fast Scarlet stain was performed and tissues viewed using polarized microscopy.