HA1 (Hemagglutinin) quantitation for influenza A H1N1 and H3N2 high yield reassortant vaccine candidate seed viruses by RP-UPLC.

The only effective measure to decrease morbidity and mortality caused by the influenza virus in the human population is worldwide vaccination. Vaccination produces neutralizing antibodies that target the HA1 subunit of the HA (hemagglutinin) protein and are strain specific. The effectiveness of new influenza vaccines are linked to two factors, the correct prediction of the circulating strains in the population in a particular season and the concentration of the HA1 protein in the vaccine formulation.

Development of high yield reassortants for influenza type B viruses and analysis of their gene compositions.

A critical step in producing the annual inactivated influenza vaccine is the development of high yield (hy) seed viruses by reassortment for improved growth in ovo. Although hy reassortants for type A influenza viruses have been developed for many years, hy B influenza reassortant virus development for vaccine production has proven difficult. In this study, we have developed fourteen hy influenza type B reassortants as vaccine candidate strains with B/Lee/40 as the donor virus.

Molecular signature of high yield (growth) influenza a virus reassortants prepared as candidate vaccine seeds.

Background: Human influenza virus isolates generally grow poorly in embryonated chicken eggs. Hence, gene reassortment of influenza A wild type (wt) viruses is performed with a highly egg adapted donor virus, A/Puerto Rico/8/1934 (PR8), to provide the high yield reassortant (HYR) viral 'seeds' for vaccine production. HYR must contain the hemagglutinin (HA) and neuraminidase (NA) genes of wt virus and one to six 'internal' genes from PR8.

Gene constellation of influenza A virus reassortants with high growth phenotype prepared as seed candidates for vaccine production.

Background: Influenza A virus vaccines undergo yearly reformulations due to the antigenic variability of the virus caused by antigenic drift and shift. It is critical to the vaccine manufacturing process to obtain influenza A seed virus that is antigenically identical to circulating wild type (wt) virus and grows to high titers in embryonated chicken eggs. Inactivated influenza A seasonal vaccines are generated by classical reassortment.