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Ligation of CD200R by CD200 is not required for normal murine myelopoiesis
Author(s) -
Rijkers Eva S. K.,
De Ruiter Talitha,
Buitenhuis Miranda,
Veninga Henrike,
Hoek Robert M.,
Meyaard Linde
Publication year - 2007
Publication title -
european journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0902-4441
DOI - 10.1111/j.1600-0609.2007.00920.x
Subject(s) - myelopoiesis , haematopoiesis , myeloid , progenitor cell , colony stimulating factor , biology , immunology , receptor , bone marrow , cancer research , microbiology and biotechnology , stem cell , biochemistry
CD200R is an inhibitory receptor involved in the regulation of myeloid cells. It recruits Dok‐1 and Dok‐2, which are potent inhibitors of the Ras signalling pathway used by colony‐stimulating factor (CSF) receptors. Dok‐1/Dok‐2 double knockout (DKO) mice develop leukaemia at 10–12 months of age. We investigated whether disturbed CD200R signalling could be responsible for this phenotype. Therefore, we studied whether CD200 −/− mice have altered myelopoiesis and develop leukaemia. We report that CD200R is expressed on haematopoietic progenitor cells. However, CD200 −/− mice have normal numbers of myeloid progenitors in the bone marrow and these cells have normal proliferative capacity. These results indicate that the development of leukaemia in Dok‐1/Dok‐2 DKO mice is not solely due to an absence of CD200R signalling. In addition, we show that the previously reported enhanced numbers of myeloid cells do not occur in all CD200 −/− mice. We determined whether variations in the numbers of peripheral myeloid cells were due to an enhanced response to granulocyte‐CSF (G‐CSF) or an inflammatory stimulus. Mobilisation of immature neutrophils via G‐CSF and infiltration of mature neutrophils and macrophages upon thioglycolate injection were not altered in CD200 −/− mice. We conclude that CD200 −/− mice exhibit normal myelopoiesis and that development of leukaemia in Dok‐1/Dok‐2 DKO mice is not caused by a lack of CD200‐mediated CD200R signalling.