Identification of the bovine α1-acid glycoprotein in colostrum and milk

Abstract

-α1-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. This paper presents the detection of bovine AGP (boAGP) in mammary secretions (colostrum and milk) and mammary gland tissue. Bovine AGP was detected by Western blotting in all the samples analysed, and could be quantified in colostrum at 162 (± 63.7) µg/mL and 114.5 (± 67.8) µg/mL during the first 12 h and 24 h respectively. In mature milk, the boAGP concentration clearly decreased and was no longer detectable using the Radial Immunodiffusion (RID) technique. The concentration of mature milk boAGP was therefore semi-quantified using an anion-exchange chromatographic procedure that allowed the concentration of the protein to be determined. The presence of AGP in bovine milk was confirmed by the internal sequence analysis performed following purification to homogeneity of the protein from milk. The concentration of AGP in bovine milk with low SCC (< 250 000) was very similar to that from bovine milk with high SCC (> 250 000). In order to investigate the origin of AGP in bovine milk, a search for mRNA was carried out in somatic cells and mammary gland tissue: mRNA expression of the boAGP gene was detected in mammary gland tissue, but not in somatic cells. Finally, the cDNA sequence of the boAGP was determined, and is hereby presented. α1-acid glycoprotein / mastitis / colostrum / milk

Effects of intramammary infection on whey proteinograms of sheep during lactation

“…We believe that it is linked to the inflammatory process of the mammary gland because it has been identified only in infected glands. Its extra-hepatic productions has been reported previously in the epithelial cells of the mammary glands of humans and cattle (Ceciliani et al 2005, Rainard & Riollet 2006, Ceciliani & Pocacqua 2007.…”

Veterinary Biomarker Discovery: Proteomic Analysis of Acute Phase Proteins

“…Evaluation of the acute phase response following experimental challenge with S. aureus revealed increases in HPT and the mammary isoform of SAA (M-SAA3) in both bovine serum and milk that were in accord with data from experimental challenge with E. coli (Eckersall et al, 2006;Grönlund et al, 2003). While the primary source of APPs is the liver, local production of SAA, HPT, and AGP in the bovine mammary gland have also been demonstrated, which mark APPs as potential indicators of both systemic and local inflammation in cattle (Larson et al, 2006;Jacobsen et al, 2005;Ceciliani et al, 2005;Hiss et al, 2004). Additionally, aside from both local and hepatic production of AGP, the granules of bovine neutrophils are likewise a reported source of APPs (Rahman et al, 2008).…”

“…Likewise, the bovine mammary gland is an established source of extra-hepatic APP production; thus the evaluation of APP expression in milk could aid in the early detection of mastitis (Hiss et al, 2004). Studies directed at the innate immune response in the bovine mammary gland following challenge with either LPS or Escherichia coli (E. coli) have reported increases in the APPs SAA, HPT, AGP, and lipopolysaccharide binding protein (LBP) in milk and serum from cows during clinical mastitis (Suojala et al, 2008;Ceciliani et al, 2005;Hiss et al, 2004;Eckersall et al, 2001;Hirvonen et al, 1999). Increases in serum concentrations of both SAA and HPT following intra-mammary challenge with E. coli were reported 24 hours after experimental infection, with peak expression of both APPs apparent on day 3 after challenge (Suojala et al, 2008;Hirvonen et al, 1999).…”

Acute Phase Proteins – Analysis, Clinical Applications and Potentials

“…AGP is considered a moderate APP in most species and is more likely to be associated with chronic conditions rather than acute inflammation. AGP is mostly synthesized during inflammation in rat, rabbit, mouse, man, cat, dog, horse and cattle but mammary-associated AGP has also been identified in bovine colostrum and milk (Ceciliani et al, 2005). AGP is a immunocalin; a group of proteins that shows significant immunomodulatory effects (Logdberg and Wester, 2000).…”