Fig. 5: Schematic diagram of gene segments in recombinant LAIV candidates.

A–C Schematic representations of the PB2 (A), HA (B), and NA (C) gene segments from different rearranged viruses, where the original viral open reading frames (ORFs) have been replaced by foreign gene ORFs. D PB1 mutant segment from a recombinant strain containing nine RNA segments expressing an additional foreign HA. The PB1 ORF is flanked by the NA packaging signal, alongside a ninth chimeric segment with the foreign HA gene from the HK strain, flanked by the PB1 packaging signal. E Rearranged H9N2 influenza A virus segments expressing an additional foreign HA. The NEP protein is positioned downstream of the PB1 gene with an autoproteolytic cleavage site (2A), and the foreign HA gene is expressed downstream of a truncated NS1 gene (NS1 1–99) with a 2A site. F Rearranged M and NS gene segments that enable independent expression of the M1/M2 and NS1/NEP proteins with 2A sites. Schematic of the Ms, NSs, and Ms/NSs gene segments. G NEP gene ORF is rearranged downstream of a truncated NS1 gene (NS1 1–128) with a 2A site.