These data show that the extent of TNFAIP3 expression in DCs controls T2/T17 cell differentiation. This implies that reducing DC activation could be a new pharmacologic intervention to treat patients with severe asthma who present with T17-mediated neutrophilic inflammation.
On the basis of somatic hypermutation status of their B-cell antigen receptor (BCR) genes, chronic lymphocytic leukemia (CLL) patients can be divided into unmutated CLL (U-CLL) or mutated CLL (M-CLL). Approximately 30% of CLL patients express a stereotypic BCR, which may indicate that specific antigenic stimulation is driving CLL pathogenesis. Recently, it was reported that BCRs from CLL cells are capable of antigen-independent, cell-autonomous signaling, through recognition of an internal framework 2 (FR2) BCR epitope. We hypothesized that the level of cell-autonomous signaling may differ between CLL subgroups. Therefore, we analyzed Ca(2+) signaling in a series of primary stereotypic or heterogeneous U-CLL and M-CLL (n=68) and healthy controls (n=14). We confirmed that basal Ca(2+) signaling in CLL cells is higher than in normal B cells. Interestingly, we found that basal signaling was particularly increased in M-CLL. The degree of basal signaling did not correlate with membrane immunoglobulin levels, HCDR3 characteristics or FR2/FR3 sequence. We conclude that the level of basal Ca(2+) signaling is not uniformly enhanced in CLL B cells, but is associated with CLL immunoglobulin heavy chain V mutational status, reflecting a distinct cellular origin and possibly a different anergic state induced by repetitive or continuous antigen binding in vivo.
Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of mature CD5+ B cells in blood. Spontaneous apoptosis of CLL cells in vitro has hampered in-depth investigation of CLL pathogenesis. Here we describe the generation of three monoclonal mouse cell lines, EMC2, EMC4 and EMC6, from the IgH.TEμ CLL mouse model based on sporadic expression of SV40 large T antigen. The cell lines exhibit a stable CD5+CD43+IgM+CD19+ CLL phenotype in culture and can be adoptively transferred into Rag1−/− mice. RNA-seq analysis revealed only minor differences between the cell lines and their primary tumors and suggested that NF-κB and mTOR signaling pathways were involved in cell line outgrowth. In vitro survival and proliferation was dependent on constitutive phosphorylation of Bruton's tyrosine kinase (Btk) at Y551/Y223, and Akt(S473). Treatment of the cell lines with small molecule inhibitors specific for Btk (ibrutinib) or PI3K (idelalisib), which is upstream of Akt, resulted in reduced viability, proliferation and fibronectin-dependent cell adhesion. Treatment of cell line-engrafted Rag1−/− mice with ibrutinib was associated with transient lymphocytosis, reduced splenomegaly and increased overall survival. Thus, by generating stable cell lines we established a novel platform for in vitro and in vivo investigation of CLL signal transduction and treatment modalities.
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