*2.7. Immunization of Animals*

To study the parameters of the immune response, we used four groups of DBA mice with 10 animals in each group. The mice from group 1 were injected with genetically modified MSCs (mMSC), mice from group 2 with non-transfected, "native" MSCs, mice from group 3 with pcNS3-NS5B plasmid, and mice from group 4 with saline. MSCs and mMSC (5 <sup>×</sup> 105 cells) were injected into the tail vein, plasmids (100 μg)—intramuscularly into the quadriceps femoris muscle. Two immunizations with an interval of 2–3 weeks were conducted.

In some experiments, the animals were injected with mMSC treated with a recombinant mouse IFN-γ protein (Abcam, Cambridge, UK) at a concentration of 80 ng/mL for 18 h. The immunization scheme was as described above.
