Identification of a secretory IgA receptor on breast-milk macrophages: evidence for specific activation via these receptors.
Binding of secretory IgA (sIgA) to human milk macrophages was identified by rosette formation with sIgA-sensitized indicator cells and competitive inhibition binding studies with [125I]-sIgA. Macrophages formed rosettes with sIgA-sensitized sheep red blood cells that were inhibited by sIgA (87%) but not IgG. Both IgA1 and IgA2 inhibited sIgA-sensitized sheep red blood cell rosette formation. Rosette formation was completely inhibited by galactose, partially inhibited by asialofetuin, and unaffected by mannose. [125I]-labeled sIgA binding to macrophages reached a plateau after 60 min, was dependent on the number of macrophages in culture, and was specifically inhibited by unlabeled sIgA. Incubation of macrophage monolayers with increasing concentrations of sIgA-anti-IgA immune complexes resulted in a progressive increase in the oxidative burst and increased secretion of prostaglandins. These studies indicate that human milk macrophages have a receptor for sIgA and that activation of these macrophages may occur via these receptors.
Robinson
G
G
Samuel Jared Kushnick Pediatric Immunology Laboratory, Department of Pediatrics, Sheba Medical Center Tel Aviv, Israel.
Volovitz
B
B
Passwell
J H
JH
D001212:Asialoglycoproteins; D015232:Dinoprostone / Q000378:metabolism; D005260:Female; D060748:Fetuins; D005690:Galactose / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis; D007071:Immunoglobulin A, Secretory / Q000276:immunology*; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D008358:Mannose / Q000494:pharmacology; D008895:Milk, Human / Q000166:cytology* / Q000276:immunology; D011961:Receptors, Fc; D011971:Receptors, Immunologic / Q000032:analysis* / Q000187:drug effects / Q000502:physiology; D012397:Rosette Formation; D000509:alpha-Fetoproteins / Q000494:pharmacology
D001212:Asialoglycoproteins; D060748:Fetuins; C068317:IgA, secretory receptor; D007071:Immunoglobulin A, Secretory; D011961:Receptors, Fc; D011971:Receptors, Immunologic; D000509:alpha-Fetoproteins; C017029:asialofetuin; D006861:Hydrogen Peroxide; D015232:Dinoprostone; D008358:Mannose; D005690:Galactose