CCR5 expression by MM cells.

(A) Surface expression of CCR5 on human MM cells and marrow stromal cells. A human MM cell line ARH77, primary MM cells from patients, and a marrow stromal cell line KM102, and a mouse stromal cell line ST-2 and a preosteoclastic cell line C7 were incubated first with mouse antihuman or mouse CCR5 antibodies or control IgG and then with an FITC-labeled secondary antibody, and were analyzed for the surface expression of CCR5 by flow cytometry as described in “Materials and methods.” (B) Expression of CCR5 mRNA. Expression of CCR5 mRNA as well as well an internal control GAPDH by ARH77 (lane 1), KM102 (lane 2), ST-2 (lane 3), and C7 (lane 4) was determined by RT-PCR analysis as described in “Materials and methods.”