Figure 3.

l-selectin shedding is inhibited by metalloproteinase inhibitors. (A) Enriched CD4⁺ T cells from huCD4tg mice were treated in vitro with a metalloproteinase inhibitor, KD-IX-73-4 or BB3103, before crosslinking of the huCD4 receptor. After 4 h, cells were stained for l-selectin expression as described in Fig. 1. Fluorescent mean values of l-selectin expression on live Th cells are shown as percentage of the untreated control. ∗, High significance (P < 0.01); ^§ no significance (P > 0.05). Results are representative of at least five experiments. (B) CFSE-labeled human CD4⁺ PBMCs were pretreated with 50 μg/ml BB3103 before exposure to NL4-3-infected (thick line) or mock-infected (thin line) Jurkat cells. After 12 h, l-selectin expression levels were determined as described in Materials and Methods.