In secondary amyloidosis of the mouse, two isotypes of serum amyloid A protein (SAA), SAA1 and SAA2, increase simultaneously after injections of azocasein. However, it has reported that only amyloid A2 (AA2), SAA2 degradate of N-terminal 75 amino-acid peptide, but not AA1, deposit as amyloid fibril. In this process, precursor SAA2 should be digested and localized on the macrophages surface in perifollicular area of the spleen. The order revealed is the localization first and then the digestion. The increased tendency of SAA adherence on the surface of the macrophages was confirmed before the deposition at 5 days after the serial injections of azocasein. Actual depostions was observed of SAA2 and the intermediate degradates (MW of 9,000 and 10,000) from 6 days after the injection, those included AA2 at the 10 day and those amount increased progressively thereafter. Isotype specific process for SAA2 depostion was confirmed in vitro experiment which showed the delayed degradation of SAA2 after both SAA1 and SAA2 were absorbed on the surface of the macrophages.
KeywordsAmyloid Fibril Secondary Amyloidosis Serial Injection Macrophage Surface Spleen Section
Unable to display preview. Download preview PDF.
- 4.Axelrad, M.A., Kisilevsky, R., et al.: Lab.Invest. 47;139, 1982Google Scholar
- 5.Baba, S., Miura, K., et al.: Vth International Symposium of Amyloidosis 1987Google Scholar
- 6.Baltz, M.L., Capsi, C.R.K., et al.: Amyloidosis ed. G.G.Glenner & E.F. Osserman et al. pll5, Plenum Press N.Y., 1984Google Scholar