[Some mechanisms of the action of oligonucleotides: stimulation of the immune system and decreased infection of the brain in tickborne encephalitis].

Morphological changes in the thymus, spleen, and brain are analyzed in white mice injected 16-component oligonucleotide (ON) pE16 complementary to the NS3 protein gene sequences of tickborne encephalitis (TBE) virus in doses of 1 to 0.001 nM. ON stimulated thymic and splenic cells. Besides the stimulating effect, injection of ON to mice infected with TBE enhanced the destruction of lymphocytes and boosted the macrophagal activity, which was paralleled by a decrease in the intensity of virus-specific injuries in the brain. Thus, the antiviral activity of ON may be due to not only the fact that it is complementary to the TBE virus genome, but to stimulation of the immune system, specifically, the thymus and T-related elements, as well.