Expression of swelling- and/or pH-regulated chloride channels (C1C-2, 3, 4 and 5) in human leukemic and normal immune cells

Chloride channels on immune cells reportedly play important roles in cell volume regulation, cell proliferation and immune functions, but they are not well characterized at the molecular level. We examined the expression of swelling-and/or pH-regulated chloride channels (CIC-2, 3, 4 and 5) in human leukemic cell lines [Jurkat and Hut-78 (T cells), Raji and Daudi (B cells), K-562 and HL-60 (myeloid cells)] and T cells, B cells and neutrophils from 8 normal subjects to clarify the difference of their expression among different cell types and maturity. Semi-quantitative RT-PCR and Northern blot analysis showed that CIC-3 was most abundantly expressed in all cells regardless of the cell types and maturity, while expression of CIC-2 was weak in these cells. Expression of CIC-4 was observed mainly in leukemic B cell lines, and in B cells and neutrophils from normal subjects. CIC-5 was expressed in all cell lines, while it was observed in only T and B cells but not in neutrophils from normal subjects. Thus, these chloride channels (CIC-2, 3, 4 and 5) showed distinct distribution among human immune cells, suggesting that they have specific roles in these cells. Molecular identification of chloride channels in leukocytes of different types and maturity may provide a new approach for the treatment of leukemia. (C) 2002 Elsevier Science Inc. All rights reserved.