Patent ID: 7851214

Claim:
An isolated batch of infectious RNA viruses for use as a vaccine, said infectious RNA viruses each comprising: (a) the entire (−)-strand sequence of a non-segmented negative-strand RNA virus of the family Paramyxoviridae which obeys the rule of six; operatively linked to (b) a foreign expressible RNA fragment, wherein the length of the genome of the infectious RNA virus is an integral multiple of six, and further wherein the infectious RNA virus is obtainable by the steps of: (1) introducing into a host cell a plasmid comprising a cDNA molecule, said cDNA molecule comprising the entire (+)-strand sequence of said negative-strand RNA virus operatively linked to an expression control sequence, which allows the synthesis of antigenomic RNA transcripts bearing the authentic 3′-termini without help of a helper virus, said host cell comprising (i) transfected nucleic acid molecules containing nucleic acid sequences that allow expression of an exogenous RNA polymerase, a viral N protein and a viral P protein, and (ii) a nucleic acid molecule containing nucleic acid sequence encoding a viral L protein; and (2) recovering and isolating the infectious RNA virus, wherein the isolated batch of infectious RNA viruses is free of helper virus.