Figure 1.

CFTR Western blot of primary immune cells and cells of immortalized cell lines. Primary immune cells (monocytes, NK cells, B cells, CD4⁺ and CD8⁺ T-cells) isolated from the peripheral blood of a healthy subject were compared in terms of their CFTR expression with undifferentiated, monocyte-like THP1 cells and differentiated, macrophage-like THP1 cells. 16HBE14o- cells served as a positive and HEK-293 cells as a negative control, respectively. Both the core-glycosylated CFTR glycoisoform (CFTR-B) and the complex glycosylated mature isoform (CFTR-C) were strongly seen in 16HBE14o- cells. All immune cells, besides undifferentiated THP1 cells, displayed bands compatible with CFTR-B in size (green arrows underneath) at 130 kDa upon Western blotting. In contrast, a CFTR-C-band (160 kDa) was seen only in the 16HBE14o-cells. Monocytes and CD4⁺ T cells also displayed undefined signals at ~95 kDa (red arrows underneath). In addition, in all cells except THP-1 and monocytes, another undefined band of ~220 kDa was detected and judged as a non-CFTR protein. It was detected by CFTR antibodies due to incorrect binding, as described previously [19]. Vinculin was used as a loading control.