Domain III peptides from flavivirus envelope protein are useful antigens for serologic diagnosis and targets for immunization.

The Flavivirus genus of the Flaviviridae family includes 70 enveloped single-stranded-RNA positive-sense viruses transmitted by arthropods. Among these viruses, there are a relevant number of human pathogens including the mosquito-borne dengue virus (DENV), yellow fever virus (YFV), Japanese encephalitis virus (JEV) and West Nile virus (WNV), as well as tick-borne viruses such as tick-borne encephalitis virus (TBEV), Langat virus (LGTV) and Omsk hemorrhagic fever (OHFV). The flavivirus envelope (E) protein is a dominant antigen inducing immunologic responses in infected hosts and eliciting virus-neutralizing antibodies. The domain III (DIII) of E protein contains a panel of important epitopes that are recognized by virus-neutralizing monoclonal antibodies. Peptides of the DIII have been used with promising results as antigens for flavivirus serologic diagnosis and as targets for immunization against these viruses. We review here some important aspects of the molecular structure of the DIII as well as its use as antigens for serologic diagnosis and immunization in animal models.