Monoclonal Anti-CCR-5 antibody may be used for flow cytometry; the antibody may be diluted to 25 μg/ml before adding 10 μL of this dilution to 1-2.5 X 106 cells. The antibody detects CCR-5 present on stimulated human PBMCs (peripheral blood mononuclear cells) only after the cells are fixed with 2% formaldehyde. The antibody does not detect CCR-5 on unfixed human PBMCs. For immunohistochemistry a working concentration of 25 μg/ml using paraffin-embedded human lymph node tissue sections.