Fig. 1 (abstract P-233).

Top Performing Vector Design Created by Switching the Relative Positions of the Light and Heavy Chain of Vector #37. The mean channel fluorescence ratio of vector #37 expressing GFP and RFP in place of the LC and HC indicated high expression from the HC-expressing cassette, providing a potential explanation for the poor titers associated with this vector design. Therefore, modifications of vectors #37 (a) and #39 (b) were created in which the relative positions of the LC and HC were switched. In addition, the orientation of the GS cassette was reversed in vector #39 with the intent to improve titers through increased selection stringency (b). IgG1 titers of select minipools during the scale-up process are shown for each vector (c-d)