CysLT1 expression in CD34⁺ hematopoietic progenitors, mature leukocytes, and cell lines.

(A) CysLT1 mRNA was expressed in CD34⁺ hematopoietic progenitor cells, mature PMNCs and MNCs, as well as in leukemic cell lines including the CD34⁺ progenitor cell line KG1a, as assessed by RT-PCR. The cell line THP-1 served as a positive control and the neuroblastoma cell line SK-N-LO as a negative control. Expression of β-actin mRNA was analyzed as a control for RNA amounts in the RT reaction. (B) Western blot analysis of CysLT1 protein expression confirmed the RT-PCR results using a polyclonal CysLT1 antibody.39 The strongest CysLT1 expression was observed in the CD34⁺ cell line KG1a. In CD34⁺ cells, CysLT1 expression was at least as strong as in mature leukocytes. (C) Circulating CD34⁺ progenitors from 3 different, additional individuals showed CysLT1 expression at a similar level.