Identification of lipopolysaccharide-binding proteins in porcine milk.
Septicemia and endotoxemia initiated by bacterial lipopolysaccharide (LPS) are relatively common in suckling and weaned piglets. Maternal milk is a source of both nutrition and immune protection for piglets. Passive transfer of colostral antibodies is necessary for protection of neonatal piglets against diseases, but the concentration of immunoglobulins in milk rapidly declines during the 1st wk of lactation in all mammals. We hypothesized, therefore, that nonimmunoglobulin substances in milk contribute to the innate protection of neonates against septicemia during the suckling period. Using LPS-affinity chromatography for isolation of LPS-binding proteins and liquid chromatography-mass spectrometry for their identification, we identified in porcine milk the following proteins with LPS-binding capacity: lactoferrin, soluble CD14, serum amyloid A, alpha-S1 casein, beta-casein, and kappa-casein. For lactoferrin, alpha-S1 casein, and kappa-casein, in vitro pepsin digestion did not inhibit LPS-binding activity, whereas combined digestion with pepsin and pancreatin abolished it. The biologic functions of these LPS-binding proteins and peptides were not determined.
Shahriar
Farshid
F
Department of Veterinary Pathology, University of Saskatchewan, Western College of Veterinary Medicine, 52 Campus Drive, Saskatoon, Saskatchewan. farshid.shahriar@usask.ca
Gordon
John R
JR
Simko
Elemir
E
D000209:Acute-Phase Proteins / Q000276:immunology* / Q000302:isolation & purification*; D000818:Animals; D000833:Animals, Suckling / Q000276:immunology; D002352:Carrier Proteins / Q000276:immunology* / Q000302:isolation & purification*; D002364:Caseins / Q000276:immunology / Q000302:isolation & purification; D002846:Chromatography, Affinity; D004926:Escherichia coli / Q000502:physiology*; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D007781:Lactoferrin / Q000276:immunology / Q000302:isolation & purification; D018950:Lipopolysaccharide Receptors / Q000276:immunology / Q000302:isolation & purification; D008562:Membrane Glycoproteins / Q000276:immunology* / Q000302:isolation & purification*; D008892:Milk / Q000737:chemistry / Q000276:immunology*; D000685:Serum Amyloid A Protein / Q000276:immunology / Q000302:isolation & purification; D013552:Swine; D000099231:Lipopolysaccharide-Binding Protein
D000209:Acute-Phase Proteins; D002352:Carrier Proteins; D002364:Caseins; D007781:Lactoferrin; D018950:Lipopolysaccharide Receptors; D008562:Membrane Glycoproteins; D000685:Serum Amyloid A Protein; D000099231:Lipopolysaccharide-Binding Protein