USING THE POLYMERASE CHAIN-REACTION TO TH E USE OF LABORATORY-ANIMALS- A PROJECT TO EXPRESS TICK-BORNE ENCEPHALITIS-VIRUS STRUCTURAL PROTEINS

Tick-borne encephalitis virus is difficult to propagate because with c onsecutive passages in cell culture the virus titer will decrease. Sto ckvirus has to be propagated in young mice. Therefore, every productio n of virus for research, diagnostic assays or vaccination demands the use of laboratory animals. WE decided to clone the part of the viral g enome which codes for the structural proteins, and to produce the stru ctural proteins in a suitable expression system. Using reverse transcr iption, followed by the polymerase chain reaction, we amplified exactl y this part of the viral genome, added restriction sites for cloning a nd a stop-codon. Cloning of this DNA-fragment and expression of the st ructural proteins of tick-borne encephalitis virus in the baculovirus expression system has thus been possible. Replacement of traditional v iral antigen by these recombinant proteins may reduce the need for lab oratory animals.