G-CSF-induced myeloid cells stimulated by TLR2 enhance engraftment after allogeneic hematopoietic stem cell transplantation

► G-CSF-mobilized myeloid cells (gMCs) in donor grafts of peripheral blood stem cell transplantation (PBSCT) constitutively express TLR2. ► Ligation of TLR2 with a specific agonist dramatically enhanced cytokine production and survival of gMCs. ► TLR2-stimulated gMCs significantly promoted myeloid differentiation of donor hematopoietic stem cells (HSCs), resulting in accelerated engraftment after allogeneic transplantation.