ADAPTATION OF BLUETONGUE VIRUS IN MOSQUITO CELLS RESULTS IN OVEREXPRESSION OF NS3 PROTEINS AND RELEASE OF VIRUS-PARTICLES

Adaptation of bluetongue virus (BTV) to grow in mosquito cells (C6/36) resulted in overexpression of two non-structural proteins (NS3 and NS 3a) in infected cells. These proteins also co-purified with BTV partic les and were dissociated from the virions upon treatment with an anion ic detergent. The expression was not host dependent, since back inocul ation of the adapted virus into mammalian cell cultures also resulted in a significant overexpression of these proteins. The BTV-C6/36 produ ced smaller plaques in Vero cells compared with the parent strain. Thi s is the first report which demonstrates a high level of NS3/NS3a expr ession in infected cells and subsequent release of infectious BTV part icles into the supernatant.