title: Dynamic development of homing receptor expression and memory cell differentiation of infant CD4+CD25high regulatory T cells.
abstract: Migration of CD4+CD25+FOXP3+ regulatory T cells (Treg) is important for suppressing immune responses in different tissues. Previous studies show that the majority of Treg at birth express gut homing receptor alpha(4)beta(7) and that only few express CCR4, while the reverse pattern is found in adults. The age at which homing receptor switch occurs in vivo is not known. In this study, we show, in a prospective study of human infants from birth to 3 years of age, that homing receptor switch from alpha(4)beta(7) to CCR4 commences between 1 1/2 and 3 years of age and that Treg at that age also had started their switch to a memory phenotype. The majority of naive Treg express alpha(4)beta(7) in infants but not in adults, while the majority of memory Treg express CCR4 both infants and adults. The homing receptor expression on Treg corresponds to their actual migration properties, because Treg from cord blood migrate foremost toward the gut-associated chemokine CCL25. CD4+FOXP3+ T cell numbers increase rapidly in the circulation during the first days of life indicating conversion to suppressive Treg from CD25(high) Treg precursors. These findings suggest that the gut is the primary site of Treg stimulation to exogenous Ags during the first 18 mo of life and that homing receptor switch toward a more extra-intestinal phenotype occurs thereafter.
authors.affiliation: Department of Rheumatology and Inflammation Research, The Sahlgrenska Academy, University of Gothenburg, Box 480, Göteborg 405 30, Sweden. hanna.grindebacke@rheuma.gu.se
authors.forename: Hanna
authors.initials: H
authors.lastname: Grindebacke
authors.forename: Hanna
authors.initials: H
authors.lastname: Stenstad
authors.forename: Marianne
authors.initials: M
authors.lastname: Quiding-Järbrink
authors.forename: Jesper
authors.initials: J
authors.lastname: Waldenström
authors.forename: Ingegerd
authors.initials: I
authors.lastname: Adlerberth
authors.forename: Agnes E
authors.initials: AE
authors.lastname: Wold
authors.forename: Anna
authors.initials: A
authors.lastname: Rudin
mesh_terms: D000328:Adult; D000367:Age Factors; D002454:Cell Differentiation / Q000276:immunology*; D002675:Child, Preschool; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D051858:Forkhead Transcription Factors / Q000096:biosynthesis / Q000097:blood; D006801:Humans; D007156:Immunologic Memory; D007223:Infant; D007231:Infant, Newborn; D016023:Integrins / Q000096:biosynthesis / Q000097:blood; D053645:Interleukin-2 Receptor alpha Subunit / Q000096:biosynthesis* / Q000097:blood; D018655:Lymphocyte Count; D008875:Middle Aged; D011446:Prospective Studies; D054398:Receptors, CCR4 / Q000096:biosynthesis / Q000097:blood; D016201:Receptors, Lymphocyte Homing / Q000096:biosynthesis* / Q000097:blood; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism*
chemical_list: C515354:CCR4 protein, human; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D016023:Integrins; D053645:Interleukin-2 Receptor alpha Subunit; D054398:Receptors, CCR4; D016201:Receptors, Lymphocyte Homing; C071777:integrin alpha4beta7