[Function of breast milk macrophages].
Human milk is a suspension of viable cells. Macrophages are the most abundant cells, comprising 40-80% of the total cell count. The present study was initiated to examine the principal cell functions of phagocytic milk macrophages: adherence, chemotaxis and phagocytosis-associated bactericidal oxidative metabolism. Adherence of milk macrophages to nylon wool was significantly decreased when compared with blood monocytes. In addition chemotaxis of macrophages in response to C 5a or a synthetic chemotactic peptide was also decreased. However, macrophages produced oxygen intermediates (O2-), H2O2) to a similar extent as blood monocytes after stimulation of the "oxidative burst" with phorbol myristate acetate or opsonized Candida particles. Macrophages cultured in vitro in endotoxin-free medium without serum lost the ability to produce oxygen metabolites over the course of a few days. Partial restoration of the oxygen radical production could be detected in macrophages exposed to bacterial lipopolysaccharide, i.e. endotoxin (LPS, 10 ng/ml). Endotoxin, which is present in the gut even of newborns might provide enough stimulation to maintain macrophages in the "primed" state. We conclude that oxygen metabolites released from milk macrophages are highly reactive and could contribute essentially to the protection of neonates against microbial infections.
D002448:Cell Adhesion; D002478:Cells, Cultured; D002633:Chemotaxis; D005260:Female; D006801:Humans; D008070:Lipopolysaccharides / Q000276:immunology; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology*; D008895:Milk, Human / Q000276:immunology*; D010587:Phagocytosis; D011247:Pregnancy; D013481:Superoxides / Q000378:metabolism
D008070:Lipopolysaccharides; D013481:Superoxides
Untersuchungen zur Funktion von Muttermilch-Makrophagen.