ANTIGENIC SIMILARITY OF CENTRAL-EUROPEAN ENCEPHALITIS AND LOUPING-ILLVIRUSES

Twenty isolates of Central European encephalitis (CEE) virus were comp ared with 20 isolates of louping-ill (LI) virus in indirect immunofluo rescence test (IIFT), using a panel of 17 monoclonal antibodies (MoAbs ) prepared against the prototype LI virus. Three Asian members of the tick-borne encephalitis (TEE) complex were also included in the compar ison: Turkish sheep encephalitis (TSE), Russian spring-summer encephal itis (RSSE) and Langat (LGT) viruses. Antigenic relationships of the v iruses were evaluated by Dice similarity coefficient and cluster analy sis. The results revealed antigenic heterogeneity of LI isolates, anti genic homogeneity of CEE isolates, and indicated that CEE and LI are r elated varieties of Eurasian TEE flavivirus that also includes TSE and RSSE strains.