FIG. 5.

Chemokine receptor expression on trCrFK cells. Expression of chemokine receptors on nontransfected CrFK cells (N) and on CrFK cells transfected stably with the human CCR3 (R3), CXCR4 (X4), or CCR5 (R5) receptor was determined by Western blot analysis (a) and FACS analysis (b through m). (a) Expression of CXCR4 was evident in all cells when anti-CXCR4 (αCXCR4) antibodies were used, but CCR3 and CCR5 proteins were detectable only in cell lines transfected with these receptors. (b through m) Surface expression of chemokine receptors was assessed by FACS analysis using nontransfected cells incubated without antibodies (b), with the secondary antibody alone (c), or with an isotype-matched antibody (d) as a control. Mock-transfected and nontransfected CrFK cells expressed CXCR4 abundantly (g and j), but minimal expression of CCR3 (e and h) or CCR5 (f and i) was detected. In contrast, a minimum of 45% of cells transfected with CCR3 (k), CCR5 (l), or CXCR4 (m) expressed their respective receptor. Representative histograms from triplicate experiments are shown.