The acute-phase protein serum amyloid A3 is expressed in the bovine mammary gland and plays a role in host defence.
The serum amyloid A protein is one of the major reactants in the acute-phase response. Using representational difference analysis comparing RNA from normal and involuting quarters of a dairy cow mammary gland, we found an mRNA encoding the SAA3 protein (M-SAA3). The M-SAA3 mRNA was localized to restricted populations of bovine mammary epithelial cells (MECs). It was expressed at a moderate level in late pregnancy, at a low level through lactation, was induced early in milk stasis, and expressed at high levels in most MECs during mid to late involution and inflammation/mastitis. The mature M-SAA3 peptide was expressed in Escherichia coli, antibodies made, and shown to have antibacterial activity against E. coli, Streptococcus uberis and Pseudomonas aeruginosa. These results suggest that the mammary SAA3 may have a role in protection of the mammary gland during remodelling and infection and possibly in the neonate gastrointestinal tract.
Molenaar
Adrian J
AJ
Dairy Science and Technology, Ruakura Research Centre, Hamilton, New Zealand. adrian.molenaar@agresearch.co.nz
Harris
D Paul
DP
Rajan
Gillian H
GH
Pearson
Monica L
ML
Callaghan
Megan R
MR
Sommer
Lilly
L
Farr
Vicki C
VC
Oden
Kim E
KE
Miles
Michelle C
MC
Petrova
Rosica S
RS
Good
Laura L
LL
Singh
Kuljeet
K
McLaren
Robert D
RD
Prosser
Colin G
CG
Kim
Kwang S
KS
Wieliczko
Robert J
RJ
Dines
Mark H
MH
Johannessen
Kirsti M
KM
Grigor
Murray R
MR
Davis
Steven R
SR
Stelwagen
Kerst
K
D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D002417:Cattle; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D008321:Mammary Glands, Animal / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D000685:Serum Amyloid A Protein / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
D017931:DNA Primers; D012333:RNA, Messenger; D000685:Serum Amyloid A Protein