Matveev et al.
Post-exposure administration of chimeric antibody protects mice against European, Siberian, and Far-Eastern subtypes of tick-borne encephalitis virus
PLoS ONE 14 (4): e0215075
In most countries, exposure treatment of a TBE infection by immunoglobulin (Ig) preparations is not permitted. The production of Ig preparations has been suspended due to concerns regarding a possible enhancement (antibody dependent enhancement, ADE) of TBE after its administration, e.g. by non-neutralizing TBE antibodies and/or too low antibody concentrations. However, in Russia the use of TBE Ig preparations is still in use. As an alternative to the use of these preparations for therapeutic treatment, a chimeric monoclonal antibody (chFVN145) which binds to epitopes in the DIII region of glycoprotein E, was been evaluated. Post-exposure treatment of mice with 100 μg or10 μg chFVN145 one day after infection with 159 LD50 TBE-Eu virus protected mice in 100% or 50%, respectively. Similar results were obtained using TBE virus subtypes Sib and FE and when treatment was started at day 2 or 3 post infection. Treatment with non-protective doses did not indicate any ADE independent of the subtypes used for infection. These results indicate that chFVN145 would be of value in designing potential anti-TBE preparations.