| First Author | Monteiro JP | Year | 2005 |
| Journal | Blood | Volume | 105 |
| Issue | 4 | Pages | 1484-91 |
| PubMed ID | 15514013 | Mgi Jnum | J:96600 |
| Mgi Id | MGI:3531028 | Doi | 10.1182/blood-2004-07-2856 |
| Citation | Monteiro JP, et al. (2005) Normal hematopoiesis is maintained by activated bone marrow CD4+ T cells. Blood 105(4):1484-91 |
| abstractText | CD4(+) T cells produce hematopoietic-related cytokines and are essential for hematopoiesis stimulation during infection and hematologic recovery after bone marrow transplantation. However, it remains unclear if T cells are necessary to maintain normal hematopoiesis. We report here that, in T-cell-deficient mice, terminal differentiation of myeloid progenitors is defective, resulting in very low levels of granulocytes in the periphery. Hematopoiesis is restored after thymus graft or reconstitution with CD4(+) T cells but not CD8(+) T cells. Bone marrow CD4(+) T cells have an activated phenotype and produce cytokines, apparently, in the absence of exogenous stimulation. Transgenic mice carrying T-cell receptor specific for an ovalbumin peptide presented in the context of a specific class II molecule (I-A(d)) (DO11.10 RAG(-/-)) show the same hematopoietic deficiency as athymic mice. Their bone marrow CD4(+) T cells are not activated, suggesting that hematopoiesis maintenance requires the presence of cognate antigen in order to activate bone marrow T-helper cells. In fact, priming of transgenic mice with ovalbumin restores normal hematopoiesis. The data show that the current concept of 'normal hematopoiesis' does not reflect a basal bone marrow activity, but it is an antigen-induced state maintained by constant activation of bone marrow CD4(+) T cells. |
