Staining of human carcinoma cells with P-selectin-IgG. Human neutrophils (PMNs), the myeloid cell line HL-60 cells, KS breast cancer cells, and SW2 small cell lung cancer cells were stained with P-selectin–IgG and FITC-conjugated goat antibodies directed against the Fc part of human IgG. The staining was done in the presence (a) or absence (b) of a blocking MoAb to human P-selectin.