A mammalian cell co-transfect with an expression plasmid comprising T7 promoter and an open reading frame (ORF) of target antigen, and a vT7 recombinant vaccinia virus expressing T7 polymerase. The entire antigen expressing cell is used as a carrier of the target antigen for preparing a vaccine or diagnostic agent, and screening monoclonal antibodies.

The present invention relates to recombinant modified vaccinia Ankara (MVA) virus containing restructured sites useful for the integration of heterologous nucleic acid sequences into an intergenic region (IGR) of the virus genome, where the IGR is located between two adjacent, essential open reading frames (ORFs) of the vaccinia virus genome, wherein the adjacent essential ORFs are non-adjacent in a parental MVA virus used to construct the recombinant MVA virus, and to related nucleic acid constructs useful for inserting heterologous DNA into the genome of a vaccinia virus, and further to the use of the disclosed viruses as a medicine or vaccine.

This present invention relates to a modified mammalian cell in which the genome of the cell is modified to comprise a sequence encoding CP77 under the control of a promoter such that the modified cell line sustains propagation of a poxvirus that is less able or unable to propagate in the unmodified cell.

Disclosed are methods of producing poxvirus-based vectors or recombinant poxvirus-based vectors from naturally derived, chemically synthesized DNA fragments, or a combination of naturally derived and chemically synthesized DNA fragments. One or more DNA sequences encoding one or more antigens, subunits or fragments thereof or other heterologous gene sequences are inserted in one or more poxvirus insertion sites in one or more DNA fragments. The methods include transfecting a host cell with one or more circular or linear DNA fragments such that a poxvirus or recombinant poxvirus is reconstituted in the host cell, the reconstituted poxvirus or recombinant poxvirus comprising the genome of a desired poxvirus. Also disclosed are poxviruses or recombinant poxviruses produced by the technology and uses thereof.

The present invention relates to a mammalian non-human cell line, specifically Chinese hamster ovary (CHO) cells, that is genetically modified to express poxvirus host range genes CP77, K1L and/or SPI-1 which are not expressed in MVA, and to the use of said cell line in the reproduction of MVA.