Induction of amyloid enhancing factor and its biological properties in murine alveolar hydatidosis

The biological activity and time of appearance of alveolar hydatid cyst induced splenic amyloid enhancing factor (AEF) with respect to amyloid deposition in the spleens were determined in C57BL/6J mice. Mice were infected intraperitoneally with 100 alveolar hydatid cysts (AHC) and killed bi-weekly between 2 and 14 weeks postinfection (p.i.). AHCs and spleens were excised, weighed and a portion of each spleen was sectioned and stained for quantitation of amyloid deposits and histological studies. The remaining spleen pieces were sonicated separately in cold phosphate buffered saline, pH 7.4 (I g/10 ml), centrifuged (27,000 g, 60 min, 4 degrees C) and the supernatant tested for AEF activity. Splenomegaly followed the progressive increase in the AHC biomass and AEF activity coincided with the appearance of amyloid deposits at 6 weeks p.i. A 2.5 mg intraperitoneal protein dosage of AEF in conjunction with a subcutaneous injection of 0.5 ml of a 0.11 M AgNO3 solution in mice, induced the maximum amount of splenic amyloid deposition at 48 h; the amount of splenic amyloid deposits decreased by either increasing or decreasing the AEF dosage. In vivo, 70% of the AEF activity was abolished by day 4 post-injection of AEF and completely by 3 weeks. These findings indicate that AHC-induced AEF is functionally analogous to casein-induced AEF and its appearance in the spleen coincides with neutrophilia, histiocytosis and amyloid deposition.