Identification of the bovine alpha 1- acid glycoprotein in colostrum and milk

The acute phase protein alpha1-acid glycoprotein (AGP) is an immunomodulatory protein expressed by hepatocytes in response to the systemic reaction that follows tissue damage caused by inflammation, infection or trauma. AGP features at least two different biological activities, apparently very different each from the other: AGP may immunomodulate the inflammatory response, and, meanwhile, act as a plasma transport protein. As the other acute phase proteins, AGP is produced mainly by hepatic cells, but local expression has been reported in human breast epithelial cells, stimulated alveolar macrophages and human endothelial cells. The detection of two of the major bovine APP, haptoglobin and serum amyloid A (SAA) in milk during mastitis may suggest a role for APP also in the immunomodulation of local inflammatory reaction in the udder. This communication presents the detection of the bovine AGP(boAGP) in mammary secretions (colostrum and milk) and mammary gland tissue.