Differential expression and secretion of bovine serum amyloid A3 (SAA3) by mammary epithelial cells stimulated with prolactin or lipopolysaccharide

• Published in: Veterinary immunology and immunopathology 2005-09, Vol.107 (3), p.255-264
• Main Authors: Larson, Marilynn A., Weber, Annika, Weber, Allen T., McDonald, Thomas L.
• Format: Article
• Language: English
• Subjects: Animals; Base Sequence; blood proteins; bovine mastitis; Bovine serum amyloid A3; Cattle - blood; Cattle - genetics; cattle diseases; Cell Line; chickens; Colostrum; dairy cows; eggs; epithelial cells; Epithelial Cells - drug effects; Epithelial Cells - metabolism; Female; flagellum; Gene Expression - drug effects; Gram-negative bacteria; immune response; Immunoblotting; In Vitro Techniques; infection; inflammation; interferons; lactation; Lipopolysaccharide; lipopolysaccharides; Lipopolysaccharides - pharmacology; macrophage activation; macrophages; Mammary gland; mammary gland diseases; Mammary Glands, Animal - cytology; Mammary Glands, Animal - drug effects; Mammary Glands, Animal - metabolism; Mastitis; mechanism of action; outer membrane proteins; phagocytosis; Prolactin; Prolactin - pharmacology; protein isoforms; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; RNA, Messenger - metabolism; Salmonella enterica subsp. enterica serovar Enteritidis; Salmonella enterica subsp. enterica serovar Typhimurium; salmonellosis; Serum Amyloid A Protein - biosynthesis; Serum Amyloid A Protein - genetics; serum amyloid A3; synergism; viability
• ISSN: 0165-2427; 1873-2534
• DOI: 10.1016/j.vetimm.2005.05.006

Serum amyloid A (SAA) proteins were originally identified as prominent acute phase serum reactants synthesized predominately by hepatocytes in response to infection, inflammation and trauma. In this study, we report the differential expression and secretion of serum amyloid A3 (SAA3) by bovine mammary epithelial cells following stimulation with either prolactin (PRL) or lipopolysaccharide (LPS). Reverse transcription-polymerase chain reaction analysis of PRL or LPS induced bovine mammary epithelial cells resulted in the detection of only the mammary-derived Saa3 ( M-Saa3) transcript. Two-dimensional immunoblot analyses of colostrum and milk from healthy cows, as well as conditioned medium from PRL or LPS stimulated bovine mammary epithelial cells confirmed the differential production and secretion of M-SAA3 while other SAA isoforms were not detected. These data indicate that the bovine Saa3 gene is regulated differently from the other Saa genes with regard to the site of and stimulus for expression, suggesting an important tissue-specific function for bovine M-SAA3 during lactation and mammary infection.