Charakterisierung eines neuen infektiösen cDNA Volllängenklons des Virus der Bovinen Virusdiarrhoe Typ 2 und Generierung von Virusmutanten Virusdiarrhoe Mucosal Disease Virus cDNS Deletionsmutante Replikon Komplementierung RNS Viren Pestivirus Volllängenklon full lenght clone Based on their genomic sequences two genotypes of Bovine viral diarrhea virus (BVDV) can be differentiated BVDV type 1 (BVDV 1) and BVDV type 2 (BVDV 2). The complete genomic sequence of the highly virulent BVDV 2 strain 890 was cloned as cDNA to establish the infectious cDNA clone p890FL. In vitro synthesised full length RNA of p890FL was transfected into bovine cells and infectious virus could be recovered (v890FL). In vitro recombinant v890FL showed similar growth characteristics as wild type virus 890WT. However infection experiments in calves revealed an attenuation of recombinant v890FL in comparison to the parental isolate. Both leukocytopenia and fever were less pronounced in v890FL infected calves. Nevertheless viremia and virus shedding were comparable between recombinant and parental BVDV 890. Furthermore mutants with partial Npro) deletions of the genomic region encoding for the autoprotease Npro (p890d dC) were constructed and characterised. In order to or the capsid protein (p890 C was efficiently trans complemented on a generate pseudovirions replicon v890 helper cell line ...