title: Redistribution of the sheep neonatal Fc receptor in the mammary gland around the time of parturition in ewes and its localization in the small intestine of neonatal lambs.
abstract: Maternal immunity is mediated exclusively by colostral immunoglobulins in ruminants. As the neonatal Fc receptor (FcRn) is suggested to be involved in the transport of immunoglobulin G (IgG) in the mammary gland, we cloned this receptor from sheep and analysed its expression in the mammary gland around the time of parturition and also in the small intestine from the newborn lamb. FcRn heavy-chain mRNA was detected (by using in situ hybridization) exclusively in the acinar and ductal epithelial cells in mammary gland biopsies both before and after parturition. Immunohistochemistry revealed that the cytoplasm of the epithelial cells of the acini and ducts in the mammary gland biopsies stained homogeneously before parturition. A remarkable difference was observed in the pattern after lambing, where the apical side of the cells was strongly stained. The presence of the FcRn in the acinar and ductal epithelial cells of the mammary gland, and the obvious change in distribution before and after parturition, indicate that the FcRn plays an important role in the transport of IgG during colostrum formation in ruminants. Immunohistochemical analysis detected a strong apical and a weak basal FcRn signal in the duodenal crypt cells of a neonatal lamb, which have been previously demonstrated to secrete IgG1 in newborn ruminants. The FcRn was not detected in the duodenal enterocytes, which absorb intact IgG from the colostrum in a non-specific manner. These data suggest that FcRn is involved in IgG1 secretion in ruminant epithelial cells.
authors.affiliation: Department of Physiology and Biochemistry, Faculty of Veterinary Science, Szent István University, H-1400 Budapest, Hungary.
authors.forename: Balázs
authors.initials: B
authors.lastname: Mayer
authors.forename: Anna
authors.initials: A
authors.lastname: Zolnai
authors.forename: László V
authors.initials: LV
authors.lastname: Frenyó
authors.forename: Veronika
authors.initials: V
authors.lastname: Jancsik
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Szentirmay
authors.forename: Lennart
authors.initials: L
authors.lastname: Hammarström
authors.forename: Imre
authors.initials: I
authors.lastname: Kacskovics
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D001483:Base Sequence; D002417:Cattle; D003001:Cloning, Molecular; D004386:Duodenum / Q000276:immunology*; D005260:Female; D015395:Histocompatibility Antigens Class I; D006801:Humans; D007112:Immunity, Maternally-Acquired; D007074:Immunoglobulin G / Q000378:metabolism; D017403:In Situ Hybridization; D007743:Labor, Obstetric / Q000276:immunology; D008321:Mammary Glands, Animal / Q000276:immunology*; D008969:Molecular Sequence Data; D011247:Pregnancy; D051381:Rats; D011961:Receptors, Fc / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D012756:Sheep / Q000276:immunology*; D013045:Species Specificity
chemical_list: D015395:Histocompatibility Antigens Class I; D007074:Immunoglobulin G; D011961:Receptors, Fc; C100688:Fc receptor, neonatal