Binding of biotinylated (Bio) CAGAS (GAS) to normal leukocytes, HL-60 cell line, and monocytic leukemia cells (MO. LEUK), which was analyzed in parallel with the binding of unconjugated anti-sLe^x (KM-93 and CSLEX-1) and anti-sLe^a (2D3 and 19.9) mouse MoAbs and biotinylated anti-i IgMk CABER (BER). The binding of CSLEX-1 to myeloid cells (PMN, MO, HL-60, and MO.LEUK) was nearly identical to that shown for Bio-GAS and KM-93. Whereas the binding of MoAb KM-93 to lymphocytes (LYMPH) was similar to that shown for BIo-GAS, CSLEX-1 MoAb bound only a few (≤9%) of these cells. Data with normal leukocytes are from 1 representaive experiment of 30 performed with cells from different healthy donors. For each donor, PMN and PBMC were obtained, and Mo and lymphocytes present in PBMCs were gated on the basis of forward and side scatter parameters. MO contained ≤0.1% of CD3⁺ cells and CD19⁺ cells, and lymphocytes contained ≤1% of CD14⁺ cells. Bound antibodies were detected by means of SA-PE and FITC-conjugated goat antibodies to mouse Igs. Negative controls (C−) for CAs and for mouse Igs were, respectively, biotinylated (Bio) polyclonal human IgM (MPoly) and unreactive isotype-matched mouse MoAbs. X-axis, Log fluorescence intensity; Y-axis, relative number of cells.