Figure 2

Integrin α4β1-targeted liposomes. (A) Schematic diagram of liposome formulations. (B) Flow cytometric analysis of THI0567-targeted liposome (250 nm, 1.0% targeting conjugate, 3 × 10⁻⁹ M) binding to Jurkat cells. Background nonspecific binding was measured in the presence of EDTA (20 mM). Three separate experiments were overlayed into one histogram. Nonspecific binding was determined in the presence of EDTA (20 mM) (C) Dose-dependent binding of THI0567-targeted liposomes (250 nm, 1.0% targeting conjugate) to Jurkat cells. Curve fitting was performed with GraphPad Prizm using a one-site binding model of total and nonspecific binding (lower graph). Liposome binding is expressed as the geometric mean fluorescence intensity (gMFI) of rhodamine B fluorescence. Data are expressed as mean ± SEM (n = 3 independent experiments). (D) Effects of particle size and targeting conjugate densities on liposome performance. Average Kds were calculated from 3 separate experiments for each liposome formulation. Abbreviations: DPPC-Dipalmitoyl phosphatidylcholine; DSPE-PEG₂₀₀₀-OMe - Distearoyl phosphoethanolamine- methoxy polyethylene glycol₂₀₀₀; THI0567 - Distearoyl phosphoethanolamine-methoxy-polyethylene glycol₃₄₀₀ –linker-THI0565; DHPE-Rhodamine - Dihexadecanoyl phosphoethanolamine (lissamine rhodamine B); DTPA-BSA-Gd - Diethylene triamine pentaacetic acid-bis(stearylamide) (gadolinium).