Figure 3. Preferential targeting of CD11ahi cells by LtxA. PBMCs from allergic asthma patients were treated in vitro with LtxA (500 ng/mL) or buffer for 24 h. The treated PBMCs were then stained with anti-CD11a antibody and Annexin V and analyzed through flow cytometry. LtxA-mediated cytotoxicity was measured in terms of apoptosis (Annexin V positive) compared with buffer treated and depletion (buffer-treated PBMCs − LtxA-treated PBMCs). (A) LtxA preferentially killed cells with high LFA-1 (defined as CD11a-positive cells with an MFI between 104 and 105) and had a negligible effect on PBMCs with low LFA-1. The significance of the differences was determined by use of Student’s t-test. (B) LtxA causes depletion of cells that express the active conformation of LFA-1 (shown in blue). PBMCs were stained with mAb24 and CD11a antibodies to identify the cells with active LFA-1. APC-A, Allophycocyanin-area; CY7, cyanine 7.
