TIM1-mediated pseudovirus internalization does not always coincide with TIM1-mediated entry enhancement.

<p>(A) Some pseudoviruses that do not use hTIM1 for productive entry are still efficiently internalized by hTIM1. Mock- or hTIM1-transduced 293T cells were infected for 2 h with purified, RT-activity normalized MLVgag-GFP pseudovirions. Uninternalized virions were detached by acid-stripping and extensive trypsinization, after which internalized virions were detected by flow cytometry. Data shown are representative of two independent experiments performed in duplicates. (B) hTIM1-mediated pseudovirus internalization is blocked by PS-containing liposomes. Mock- or hTIM1-transduced 293T cells were preincubated for 20 min at room temperature with medium alone (none), or with liposomes consisting of either 50% PS and 50% PC (PS/PC) or PC alone (PC). MLVgag-GFP pseudovirions, prepared as in A, were then added for a 2 h infection at 37°C, after which bound virions were detached and internalized virions were detected as in A. Figure shows mean+SD of two independent, duplicated experiments.