Defective eosinophil hematopoiesis ex vivo in inbred Rocky Mountain White (IRW) mice.
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ABSTRACT: We examine the proliferation and differentiation of bone marrow (BM) progenitors from inbred Rocky Mountain White (IRW) mice, a strain used primarily for retrovirus infection studies. In contrast to findings with BALB/c and C57BL/6 strains, IRW BM cells cannot proliferate or generate pure eosinophil cultures ex vivo in response to a defined cytokine regimen. Analysis of IRW BM at baseline was unremarkable, including 0.08 ± 0.03% Lin(-)Sca-1(+)c-kit(+) (LSK) hematopoietic stem cells and 5.2 ± 0.3% eosinophils; the percentage of eosinophil progenitors (EoPs; Lin(-)Sca-1(-)c-kit(+)CD34(+)IL-5R?(+)) was similar in all three mouse strains. Transcripts encoding GM-CSFR? and the IL-3/IL-5/GM-CSF common ? chain were detected at equivalent levels in IRW and BALB/c BM, whereas expression of transcripts encoding IL-5R?, IL-3R?, and GATA-2 was diminished in IRW BM compared with BALB/c. Expression of membrane-bound IL-5R? and intracellular STAT5 proteins was also diminished in IRW BM cells. Diminished expression of transcripts encoding IL-5R? and GATA-2 and immunoreactive STAT5 in IRW BM persisted after 4 days in culture, along with diminished expression of GATA-1. Western blot revealed that cells from IRW BM overexpress nonsignaling soluble IL-5R? protein. Interestingly, OVA sensitization and challenge resulted in BM and airway eosinophilia in IRW mice; however, the responses were significantly blunted. These results suggest that IRW mice have diminished capacity to generate eosinophils in culture and in vivo, likely as a result of diminished signaling via IL-5R?.
SUBMITTER: Dyer KD
PROVIDER: S-EPMC3236555 | biostudies-literature | 2011 Dec
REPOSITORIES: biostudies-literature
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