BOTH MURINE SAA(1) AND SAA(2) YIELD AA AMYLOID IN ALVEOLAR HYDATID CYST-INFECTED MICE

Amyloid susceptible C57BL/6 and partially amyloid resistant A/J mice, infected intraperitoneally with 250 alveolar hydatid cyst (AHC), the l arval stage of ii cestode parasite Echinococcus multilocularis, develo p multiple organ amyloid deposits at approximately 1 and 4 weeks post infection (p.i.), respectively. Pooled spleens and livers from each mo use strain, at 8 and 10 weeks p.i., were used for the purification of protein AA utilizing a HiLoad Superdex 200 column equilibrated with 5M guanidine-HCl. Protein AA from each mouse strain was separated on 16% Tris-tricine SDS-PAGE gels and immunoblotted with monospecific rabbit anti-mouse AA IgG; five and six immunoreactive AA subspecies were det ected in the C57BL/6 and A/J materials, respectively. N-Terminal amino acid sequence analysis was performed on the bulk column-purified prot ein AA as well as on the electroblotted AA subspecies from each mouse strain. The results show a mixture of serum amyloid A(1) (SAA(1)) and (SAA(2))-derived AA protein from each mouse strain; SAA(1)-derived AA, although alluded to, has never been demonstrated as tissue deposits i n mice. These findings suggest that the intense and persistent inflamm atory processes in AHC-infected mice may have induced conversion of we akly amyloidogenic SAA(1) to AA. This conversion could be detected by amino acid sequencing of electrophoretically separated AA subspecies.