Expression of PSGL-1 in the thymuses of BM chimeras. After irradiation, normal (A-B) and L-selectin-deficient (C-D) C57BL/6 mice were reconstituted with syngeneic BM cells collected from normal (A,C) or L-selectin-deficient (B,D) mice, as described in “Materials and methods.” After 4 weeks, the thymocytes were analyzed for PSGL-1 expression by flow cytometry using the PSGL-1-specific mAb antibody (dark line). (E) Flow cytometric analysis of PSGL-1 (dark line) on KOL1682 lymphoma cell line. Control included incubation with the phycoerythrin (PE) conjugate alone. FL-2 indicates fluorescence intensity.