Fig. 4
![Fig. 4](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12985-024-02350-w/MediaObjects/12985_2024_2350_Fig4_HTML.png)
Western blot analysis of sucrose gradient-purified influenza viruses and a recombinant RBD protein using: A anti-RBD rabbit polyclonal antibody (*) – influenza HA monomer with RBD insertion; (♦) – monomeric recombinant RBD (♦♦) – dimeric form of RBD; the higher bands are oligomers of these forms; B anti-H7 HA mouse hyperimmune sera. (*) – influenza H7 HA monomer with RBD insertion is higher than H7 HAs without insertions (triangle); Cov19: FluCoVac-19. Cov20: FluCoVac-20. The H7N9 LAIV vector (H7N9) and recombinant RBD protein (RBD) were used as control antigens in this assay