Fig. 5. Replacement of Tyr230 by an Arg in a truncated DRß molecule partially restores Iip35 egress. HEK 293T cells were transiently co-transfected with the indicated chimeric molecules and with pREP4 Iip35 LI/ML and tested after 48 hours. Cells were analysed by flow cytometry using BU45 either before (surface Ii) or after (total Ii) permeabilization with saponin. The ratios of surface to total Ii are shown. The total ISCR3 mean fluorescence value (MFV) for all the chimeric class II molecules was between 235 and 255. The MFV for the secondary antibody alone was 5 (data not shown).