Animals
The CCR5 wild type (CCR5+/+) and CCR5 knockout (CCR5−/−) mice were purchased from The Jackson Laboratory (Bar Harbor, Maine 04609 USA). The mice were housed and bred under specific pathogen free conditions at the Laboratory Animal Research Center of Chungbuk National University, Korea. The mice (n = 4/cage) were maintained in a room with a constant temperature of 22±1°C, relative humidity of 55±10%, and 12-h light/dark cycle, and fed standard rodent chow (Samyang, Korea) and purified tap water ad libitum. The CCR5+/+ mice (n = 20) and CCR5−/− mice (n = 20), that were used, had matched ages (10–11 weeks old) and weights (16–19 g). Control mice (B6129PF2/J) were F2 hybrid mice from the C57BL/6J-AW-J and 129P3/J parental strains. CCR5 mice (B6, 129P2-Ccr5tm1Kuz/J) have the entire coding region of the CCR5 gene deleted from the parental strains, B6;129P2-Ccr5tm1kuz and B6;129P2-Cmkbr5tm1Kuz.