Ingested soluble CD14 from milk is transferred intact into the blood of newborn rats.
BACKGROUND
Milk acts as an edible immune system that is transferred from mother to newborn. Soluble Cluster of Differentiation 14 (sCD14) is a protein found in significant quantities in human milk (~8-29 µg/ml). At a 10-fold lower concentration in the blood (~3 µg/ml), the most notable role of sCD14 is to sequester lipopolysaccharides of Gram-negative bacteria from immune cells.


METHODS
To explore the pharmacodynamics of this milk protein and its biological fate, the biodistribution of radiolabeled sCD14 ((14)C, (125)I) was monitored in 10-d-old rat pups.


RESULTS
Up to 3.4 ± 2.2% of the radiolabeled sCD14 administered was observed, intact, in the pup blood for up to 8 h post-ingestion. Additionally, 30.3 ± 13.0% of the radiolabeled sCD14 administered was observed degraded in the stomach at 8 h post-ingestion. A reservoir of intact, administered sCD14 (3.2 ± 0.3%), however, remained in the stomach at 8 h post-ingestion. Intact sCD14 was observed in the small intestine at 5.5 ± 1.6% of the dose fed at 8 h post-ingestion.


CONCLUSIONS
The presence of intact sCD14 in the blood and the gastrointestinal tract of newborns post-ingestion has implications in the development of allergies, obesity, and other inflammation-related pathogeneses later in life.
Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.
Tonya L
TL
Ward
Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.
William J
WJ
Spencer
Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.
Laura D R
LD
Davis
1] Department of Pediatrics, University of Ottawa, Ottawa, Ontario, Canada [2] Neonatal Intensive Care Unit, Gastroenterology, Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.
Joann
J
Harrold
1] Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada [2] Department of Pediatrics, University of Ottawa, Ottawa, Ontario, Canada [3] Neonatal Intensive Care Unit, Gastroenterology, Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.
David R
DR
Mack
Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.
Illimar
I
Altosaar
D000818:Animals; D000831:Animals, Newborn; D041981:Gastrointestinal Tract / Q000378:metabolism; D006801:Humans; D007249:Inflammation; D018950:Lipopolysaccharide Receptors / Q000097:blood* / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000737:chemistry; D008892:Milk / Q000737:chemistry*; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry; D013997:Time Factors; D014018:Tissue Distribution
D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D011994:Recombinant Proteins