title: Recombinant expression of goat milk serum amyloid A: preliminary studies of the protein and derived peptides on macrophage phagocytosis.
abstract: Serum Amyloid A3 (SAA3) protein is a member of a complex group of acute phase and constitutive proteins which have been related to several immune functions. Bovine milk SAA3 (M-SAA3) has been described to have a unique N-terminal TFLK motif responsible for up regulating mucin expression in the intestine lumen and therefore a protective gastrointestinal role. cDNA sequences encoding the protein goat M-SAA3 were successfully cloned from milk, mammary gland tissue and liver, expressed despite observed toxicity and purified as a soluble protein. Sequence analyses of the milk and liver derived forms revealed a non mammary-restricted common N-terminal TFLR motif, unlike that described for bovine M-SAA3. Serum derived forms of SAA have been described to opsonize Gram-negative bacteria facilitating their phagocytosis by circulating macrophages or intestinal epithelial cells. However, no reports about a possible opsonic mechanism of the SAA3 isoforms have been described. Recombinant protein but not peptides encompassing the TFLR region increased blood and milk macrophage interaction and uptake of bacteria reported as number of bacteria per 100 macrophages and percentage of macrophages containing one or more bacteria. gMSAA3-derived peptides did not show any effect on phagocytosis. This would indicate that the TFLK-like region responsible for the up-regulation of mucins in the intestine is not the functional part of g-MSAA3 in promoting macrophage phagocytosis.
authors.affiliation: Ruminant Department of IRTA, Institute of Research in Agriculture and Technology, Barcelona, Spain. anna.domenech@irta.es
authors.forename: Anna
authors.initials: A
authors.lastname: Domènech
authors.forename: John Graham
authors.initials: JG
authors.lastname: Raynes
authors.forename: Eduardo Graham
authors.initials: EG
authors.lastname: Rodríguez
authors.forename: Anna
authors.initials: A
authors.lastname: Arís
authors.forename: Alex
authors.initials: A
authors.lastname: Bach
authors.forename: Alicia
authors.initials: A
authors.lastname: Serrano
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003001:Cloning, Molecular; D015870:Gene Expression; D005818:Genetic Engineering / Q000379:methods*; D006041:Goats; D006801:Humans; D008099:Liver / Q000378:metabolism; D008264:Macrophages / Q000166:cytology* / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000378:metabolism; D008892:Milk / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D010587:Phagocytosis; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D017421:Sequence Analysis; D000685:Serum Amyloid A Protein / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D011994:Recombinant Proteins; D000685:Serum Amyloid A Protein