*2.4. Immunochemical Staining of Products of Transfected Cells*

The presence of target proteins in eukaryotic cells 293T transfected with pEV.CTL and pEV.Th was detected through immunostaining. Cell transfection was carried out using MATra-A reagent according to the manufacturer's instruction (PromoKine, Germany). Cells were cultured in DMEM medium with 10% FBS. 32 h after transfection cells were washed in phosphate buffer solution (PBS), fixed in a mix of ice methanol/acetone (1:1) at 40 ◦C for 30 min, and then washed in PBS again. The expression products of *EV.CTL* and *EV.Th* gene were detected in immunochemical staining. Staining was carried out using antibodies MAT 29F2/30A6 (JSC Vector-Best, Novosibirsk, Russia) to marker epitope EPFRDYVDRFYKTL being a part of all constructs, and using conjugate of rabbit

antibodies to mice IgG with horseradish peroxidase. When staining, 3.3- -Diaminobenzidine was used as substrate.
