Fig. 7.

PCR analysis of CXCR4 and CCR5 chemokine receptor expression as a function of IL-2. RNA and subsequently, cDNA was prepared from either IL-2 dependent MCH5-4 cells or IL-2 independent MCH5-4DL cells. PCR was then performed as detailed in Section 2, to quantitate the expression of CXCR4 and CCR5 vs. a concentration gradient of exogenous IL-2. Quantitation of β-actin was used as a control for standardizing target cDNA (upper panel). The amount of CXCR4 mRNA was constant, regardless of cell type or level of exogenous IL-2 (middle panel). In the absence of exogenous IL-2, the expression of CCR5 was markedly reduced in MCH5-4 cells, but was upregulated in the presence of IL-2.