Mechanisms of Protective Actions of Specific Antibodies against the Tick-Borne Encephalitis Virus

The protective mechanisms of specific antibodies against tick-borne encephalitis virus were demonstrated on in vitro model. The effect of specific IgG on tick-borne encephalitis virus was comprehensively assessed in virucidal, preventive, direct antiviral, and intracellular actions by ELISA and virus titration results. The IC₅₀ values were obtained for virucidal (3.8±0.7 U/ml), preventive (42.8±9.9 U/ml), direct antiviral (7.2±0.9 U/ml), and intracellular action (1.7±0.4 U/ml). During titration of the samples, complete elimination of the virus was observed at IgG concentration of 16 U/ml (virucidal), 320 U/ml (preventive), 32 U/ml (direct antiviral), and 8 U/ml (intracellular action). It was demonstrated that specific IgG produces a complex inhibitory effect on tick-borne encephalitis virus: it possesses both direct neutralizing activity on the virus and reduces its adsorption and intracellular replication.