Detection of Serum Amyloid A Isoforms in Cattle

Two-dimensional electrophoresis and immunoblotting were used to characterize 7 serum amyloid A (SAA) isoforms in cows with amyloidosis or chronic inflammation. Five SAA isoforms (isoelectric point [pI] 5.6, 6.1, 6.4, 6.8, and 7.7) were detected in all 10 amyloidosis serum samples, while 2 isoforms, pI 5.2 and 8.6, were detected in 4 and 9 of the samples, respectively. The same 7 isoforms were also detected in the serum of cows with chronic inflammation, but SAA pI 5.2 and 8.6 were detected in only 1 and 2 of 10 samples, respectively. It was concluded that although an amyloid-specific SAA isoform was not detected, examination of SAA isoform detection patterns may help identify bovine amyloidosis.