N-terminal sequence analysis of SAA-derivatives purified from murine inflammatory macrophages.
The pathogenesis of secondary amyloidosis in vivo is not well-understood. Experimental studies suggest that incomplete degradation of acute phase serum amyloid A (SAA), presumably endocytosed by activated monocytoid cells, may lead to intralysosomal formation of amyloid A (AA). To establish a possible link between these two events, we have carried out partial N-terminal sequence analysis of affinity purified SAA derivatives from peritoneal macrophages isolated at 4 weeks post-infection from alveolar hydatid cyst infected C57BL/6 mice. The macrophage lysates yielded five N-terminally intact SAA derivatives of approximately 5 to approximately 12 kDa which reacted with anti-mouse AA IgG, and contained a mixture of SAA1 and SAA2 isoforms. The SAA2:SAA1 ratio, evaluated from their proportion present in each M(r) SAA derivative, showed a decrease with the decreasing apparent mass of the N-terminally infected SAA material. These results not only confirm that both SAA1 and SAA2 are processed by activated monocytoid cells but, more importantly, establish a plausible link between N-terminally intact SAA derivatives and formation of AA within activated monocytoid cells.
Bell
A W
AW
Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.
Chan
S L
SL
Ali-Khan
Z
Z
D000595:Amino Acid Sequence; D000818:Animals; D001053:Apolipoproteins / Q000737:chemistry / Q000302:isolation & purification*; D015153:Blotting, Western; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D017737:Macrophages, Peritoneal / Q000737:chemistry*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D000685:Serum Amyloid A Protein / Q000737:chemistry / Q000302:isolation & purification*
D001053:Apolipoproteins; D000685:Serum Amyloid A Protein