Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Vaccination against tick-borne encephalitis virus, a flavivirus, prevents disease but not infection, although viremia is undetectable.

Abstract

By adoptive transfer of sera or immunoglobulin preparations, vaccine-induced protection against tick-borne encephalitis (TBE) virus has been demonstrated to be mediated by antibodies to the surface protein of TBE virus, glycoprotein E. Nevertheless, the mechanism of vaccine-induced protection against TBE virus remains unclear. Protection by E antibodies without in vitro neutralization was shown by one group, whereas others found a correlation between protection in vivo and neutralization in vitro. The authors confirm in a mouse model of TBE that immunization with the whole-killed virus vaccine protects mice against a subsequent challenge with a highly lethal dose of virus, i.e. 250 LD50 doses. Vaccine-induced immunity, however, is not completely neutralizing, as demonstrated by the development of immune responses to a non-structural virus protein absent from the vaccine, yet expressed in the course of virus replication. Antibodies specific for the non-structural protein 1 (NS1) and cytotoxic T-cells could be detected after, but not prior to, virus challenge of vaccinated animals, establishing that protection by this highly effective vaccine is not equivalent with complete neutralization of the challenge virus.