Expression of IL-5Ralpha on B-1 cell progenitors in mouse fetal liver and involvement of Bruton's tyrosine kinase in their development.
B-1 cells are a subset of B cells responsible for the production of natural antibodies. Although the amount of natural antibody is tightly regulated, how this regulation occurs remains unknown. We examined the expression of IL-5 receptor, a cytokine receptor critical for homeostatic proliferation of B-1 cells, on B-1 cell progenitors in the fetal liver. We identified B-1 progenitors expressing low levels of IL-5 receptor alpha chain (IL-5Ralpha) and eosinophil progenitors expressing higher levels of IL-5Ralpha in the fetal liver. Moreover, the number of these B-1 progenitors were significantly reduced in the fetuses of mice deficient in Bruton's tyrosine kinase (Btk), even though IL-5 and thymic stroma lymphopoietin signaling are intact in early B lineage cells in Btk-deficient mice. These data suggest that IL-5 is possibly involved in B-1 cell development and an uncharacterized, Btk-dependent regulatory signaling pathway is involved in unexpectedly early stages of B-1 cell differentiation.
Department of Immunology, Division of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Japan. kourot@nibio.go.jp
Taku
T
Kouro
Masashi
M
Ikutani
Ai
A
Kariyone
Kiyoshi
K
Takatsu
D000077329:Agammaglobulinaemia Tyrosine Kinase; D000818:Animals; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000276:immunology* / Q000378:metabolism; D004804:Eosinophils / Q000201:enzymology / Q000276:immunology; D005333:Fetus / Q000276:immunology; D053666:Interleukin-5 Receptor alpha Subunit / Q000276:immunology*; D008099:Liver / Q000196:embryology / Q000201:enzymology / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D054448:Precursor Cells, B-Lymphoid / Q000201:enzymology / Q000276:immunology*; D011505:Protein-Tyrosine Kinases / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology; D000094632:Thymic Stromal Lymphopoietin
D016207:Cytokines; D053666:Interleukin-5 Receptor alpha Subunit; C527275:interleukin-5- receptor alpha, mouse; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625951:Btk protein, mouse; D000094632:Thymic Stromal Lymphopoietin; C000721967:TSLP protein, mouse