Methods to produce bunyavirus replicon particles

Method for generating a recombinant bunyavirus replicon particle, the method comprising:

• A) providing a eukaryotic cell with growth medium;
• B1) providing the eukaryotic cell with T7 polymerase;
• B2) providing the eukaryotic cell with bunyavirus (NSm)GnGc protein:
• B3) providing the eukaryotic cell with a vector that encodes a bunyavirus L genome segment, which is flanked by a T7 promoter and cDNA of a ribozyme sequence;
• B4) providing the eukaryotic cell with a vector that encodes at least part of a bunyavirus S genome segment comprising the N-gene and the 3′ and 5′ UTRs, which is flanked by a T7 promoter and cDNA of a ribozyme sequence;
• and, optionally,
• B5) providing the eukaryotic cell with a vector that comprises a bunyavirus M genome segment from which the GnGc coding region has been functionally inactivated, the cDNA of the genome segment being flanked by a 17 promoter and cDNA of a ribozyme:
• C) generating a recombinant bunyavirus replicon particle which can be isolated from the growth medium;
• wherein the sequence of steps B1, B2, B3, B4, B5 is random and all or part of these steps may be performed simultaneously.