Fig. 2

The expression of TLR9 in normal B cells and B-cell malignancies. TLR9 is expressed heterogeneously at almost all stages of B cell development. B cell precursors (+^◊) grown in Iscove’s modified Dulbecco’s media with recombinant IL-7 express different levels of TLR9. Memory B cells express higher levels of TLR9 (+++) than naive B cells (+) and germinal center B cells (++). In addition, B cell malignancies arising from different stages of B cells also express TLR9. Although the exact expression levels of TLR9 in these cells remain unknown, activation of TLR9 causes surface marker upregulation and cytokine secretion according to in vitro experiments (+*) and clinical data (+^Δ) (CLL chronic lymphocytic leukemia, BL Burkitt lymphoma, NHL non-Hodgkin lymphoma, MM multiple myeloma, GC B cells germinal center B cells, FL follicular lymphoma, DLBCL diffuse large B cell lymphoma, MZLs marginal zone lymphomas, MCL mantle cell lymphoma, pre-B cells precursor B cells, SLL small lymphocytic lymphoma, ALL acute lymphocyte leukemia)