Western blot and quantitative PCR demonstrate that CCR5 protein and mRNA are only present in cells expressing surface CCR5. (A) Western blots of CCR5⁺ and CCR5⁻ Sorted whole cell lysates. CD3⁺ T cells from the whole blood of 3 different donors were isolated and sorted by flow cytometry into CCR5⁻ and CCR5⁺ populations. Lysates were made from the 2 populations, and CCR5 was detected by Western blot (band at ∼ 42 kDa). Lysates from parental and Hi-5 GHOST (3) cell lines were used as negative and positive controls, respectively. β-actin was used as a loading control for each lysate (band at ∼ 47 kDa). (B) CCR5 mRNA in CCR5⁺ and CCR5⁻ sorted cells. Median copy number of CCR5 mRNA was normalized to median copy number of R18 mRNA, and values were multiplied by 1 000 000. Samples were run in duplicate for a given dilution, and all wells in range of the standard curve for a given sample were used to calculate the median values shown.