Dose-response relationship between the levels of peptide-encoding RNA within the cell and peptide/MHC molecules on the cell surface. EL4 cells were electroporated (settings 300 V/150 μF) with different amounts of Sec-SIINFEKL-A(67)ACUAG RNA. Transfected cells harvested at different time points were stained with 25D1.16 antibody to determine surface SIINFEKL/K^b-complexes. Concentrations of SIINFEKL peptide were calculated from the mean fluorescence values of viable cells using a peptide titration as standard curve.