Design and activity analysis of second-generation MIP-1α/RANTES chimeras. (A) Design of second-generation MIP-1α/RANTES chimeras: muMIP-1α sequences are represented by bold lines and hRANTES sequences are represented by dotted lines. The conserved cysteine residues are represented by the letter C. L indicates loop; T, turn; and B, β-sheet. (B) Effects of second-generation chimeras on CFU-A colony growth: all wild-type and chimeric chemokines were tested at 100 ng/mL by direct addition to the assay plates. In this assay, the average number of CFU-A colonies per control plate was 6.2 ± 1.3. Results are expressed as a percentage of CFU-A colony growth plus or minus SEM, as in Figure 2. ns indicates not significant; ^*P = .014; and ^**P < .001. This assay is representative of 3 repeat assays.