Scheme of construction of NYVAC-C-KC-ΔB19R.

<p>To insert <i>C7L</i> and <i>K1L</i> back into the NYVAC genome, each gene plus a corresponding portion of the flanking regions was amplified by PCR. The two fragments were combined into one fragment using PCR. The entire cassette, containing <i>C7L</i> and <i>K1L</i> plus flanking regions homologous to the adjacent genes of the NYVAC genome (<i>C8L</i> and <i>K2L</i>), was inserted into NYVAC-C by <i>in vivo</i> recombination. To create NYVAC-C-KC-ΔB19R, the KC fragment was inserted into NYVAC-C-ΔB19R by the same method. IGR: Intergenic region.</p>