CD19 and infection: To test the specificity of the anti-CD19 typed lentivirus, we transduced 2 × 106 CD19+ and 2 × 106 CD19− 293FT cells by spin infection with 107 transducing units of concentrated anti-CD19 psudotyped virus or with VSVG pseudotyped control viruses and assayed expression by flow cytometry and immunofluorescence.