title: Neonatal microbial colonization in mice promotes prolonged dominance of CD11b(+)Gr-1(+) cells and accelerated establishment of the CD4(+) T cell population in the spleen.
abstract: To assess the microbial influence on postnatal hematopoiesis, we examined the role of early life microbial colonization on the composition of leukocyte subsets in the neonatal spleen. A high number of CD11b(+)Gr-1(+) splenocytes present perinatally was sustained for a longer period in conventionally colonized (CONV) mice than in mono-colonized (MC) and germfree (GF) mice, and the CD4(+) T cell population established faster in CONV mice. At the day of birth, compared to GF mice, the expression of Cxcl2 was up-regulated and Arg1 down-regulated in livers of CONV mice. This coincided with lower abundance of polylobed cells in the liver of CONV mice. An earlier peak in the expression of the genes Tjp1, Cdh1, and JamA in intestinal epithelial cells of CONV mice indicated an accelerated closure of the epithelial barrier. In conclusion, we have identified an important microbiota-dependent neonatal hematopoietic event, which we suggest impacts the subsequent development of the T cell population in the murine spleen.
authors.affiliation: Department of Veterinary Disease Biology, Faculty of Health Medical Sciences, Section of Experimental Animal Models, University of Copenhagen 1870 Frederiksberg C, Denmark ; Department of Food Microbiology, National Food Institute, Technical University of Denmark 2860 Søborg, Denmark.
authors.forename: Matilde B
authors.initials: MB
authors.lastname: Kristensen
authors.affiliation: Department of Veterinary Disease Biology, Faculty of Health Medical Sciences, Section of Experimental Animal Models, University of Copenhagen 1870 Frederiksberg C, Denmark.
authors.forename: Stine B
authors.initials: SB
authors.lastname: Metzdorff
authors.affiliation: Department of Food Microbiology, National Food Institute, Technical University of Denmark 2860 Søborg, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Bergström
authors.affiliation: Department of Veterinary Disease Biology, Faculty of Health Medical Sciences, Section of Experimental Animal Models, University of Copenhagen 1870 Frederiksberg C, Denmark.
authors.forename: Dina S M
authors.initials: DS
authors.lastname: Damlund
authors.affiliation: Novo Nordisk, Novo Allé 2880 Bagsværd, Denmark.
authors.forename: Lisbeth N
authors.initials: LN
authors.lastname: Fink
authors.affiliation: Department of Food Microbiology, National Food Institute, Technical University of Denmark 2860 Søborg, Denmark.
authors.forename: Tine R
authors.initials: TR
authors.lastname: Licht
authors.affiliation: Department of Veterinary Disease Biology, Faculty of Health Medical Sciences, Section of Experimental Animal Models, University of Copenhagen 1870 Frederiksberg C, Denmark.
authors.forename: Hanne
authors.initials: H
authors.lastname: Frøkiær
keywords: CD11b+Gr-1+ myeloid cells; CD4+ T cells; microbiota; neonatal hematopoiesis