Reverse genetics vaccine seeds for influenza: Proof of concept in the source of PB1 as a determinant factor in virus growth and antigen yield.

Growth deficits of reverse genetics vaccine seeds have compromised effective immunization. The impairment has been attributed to sub-optimal protein interactions. Some level of dependence may exist between PB1 and antigenic glycoproteins, however, further research is necessary to clarify the extent to which it can be used in favor of seed production. Our objective was to establish proof of concept on the phenotypic outcome of PB1 source in the PR8: A(H1N1)pdm09 reassortants. Reassortants were generated with the gene constellation of the classical 6:2 PR8: HA, NApdm09 seed prototype and the 5:3 reassortant PR8: HA, NA, PB1pdm09. Viral growth and antigen yield were evaluated 12-60h post-infection. The 5:3 reassortant presented statistically significant growth and antigen yield improvements when compared to the 6:2. We believe these findings to be of promising value to vaccine research towards an improvement of reverse genetic seeds, an overall more cost-effective vaccine manufacture and timely delivery.