Most autoreactive B cells are normally counterselected during early B cell development. To determine whether Toll-like receptors (TLRs) regulate the removal of autoreactive B lymphocytes, we tested the reactivity of recombinant antibodies from single B cells isolated from patients deficient for IL-1R-associated kinase (IRAK)-4, myeloid differentiation factor 88 (MyD88) and UNC-93B. Indeed, all TLRs except TLR3 require IRAK-4 and MyD88 to signal and UNC-93B-deficient cells are unresponsive to TLR3, TLR7, TLR8 and TLR9. All patients suffered from defective central and peripheral B cell tolerance checkpoints resulting in the accumulation of large numbers of autoreactive mature nave B cells in their blood. Hence, TLR7, TLR8, and TLR9 may prevent the recruitment of developing autoreactive B cells in healthy donors. Paradoxically, IRAK-4-, MyD88- and UNC-93B-deficient patients did not display autoreactive antibodies in their serum nor developed autoimmune diseases, suggesting that IRAK-4, MyD88 and UNC-93B pathway blockade may thwart autoimmunity in humans.
IRAK-4- and MyD88-dependent pathways are essential for the removal of developing autoreactive B cells in humans.
No sample metadata fields
View SamplesFunctional characterization of human dendritic cell subsets is limited due to the very low frequency of these cells in vivo. We developed an in vitro culture system for the simultaneous generation of XCR1+ DCs and MoDCs from cord blood CD34+ cells. Their global gene expression profiles at steady state and under activation, phenotypes, morphologies and responses to different TLR ligands where characterized and compared with those of their in vivo counterparts. The study demonstrated that the XCR1+ DCs generated in vitro from cord blood CD34+ cells are equivalent to blood XCR1+ DCs and also allowed a rigorous comparison of this DC subset with MoDC which are often considered as the reference model for DCs. Altogether, our results showed that in vitro generated XCR1+ DCs are a better model for the study of blood DC than the conventionally used MoDCs.
Human XCR1+ dendritic cells derived in vitro from CD34+ progenitors closely resemble blood dendritic cells, including their adjuvant responsiveness, contrary to monocyte-derived dendritic cells.
Specimen part, Treatment
View Samples