Development and identification of a new Vero cell-based live attenuated influenza B vaccine by a modified classical reassortment method

ABSTRACT

Background: It was to generate a new Vero and cold-adapted live attenuated influenza B vaccine with enough safety and immunogenicity.

Methods: According to modified classical reassortment method, the donor strain was B/Yunnan/2/2005Vca(B), and the parental virus strain was B/Brisbane/60/2008wt. After co-infection in Vero cells, the prepared antibody serum inhibited the donor strain growth, and screening conditions inhibited the parental virus growth, which induced the growth of the new reassortant virus B/Brisbane/60/2008Vca(B) grow. Through intraperitoneal injection (i.j.) and intranasal injection (n.j.) we evaluated the safety and immunogenicity of the vaccine.

Results: A high-yield of the reassortant virus was produced in Vero cells at 25°C, similar to the donor strains. After sequencing, it was found that B/Brisbane/60/2008Vca(B) Hemagglutinin (HA) and Neuraminidase (NA) gene fragments were from B/Brisbane/60/2008wt, while the other 6 gene fragments were from B/Yunnan/2/2005Vca(B). The n.j. immune pathway experiments showed no significant differences between the treatment and the PBS control group with respect to weight changes (P > 0.5). Furthermore, the new strain had a sufficient geometric mean titter (GMT) against B/Brisbane/60/2008wt.

Conclusion: The new reassortant live attenuated influenza B vaccine was safe and having enough immune stimulating ability.

KEYWORDS:

• Influenza B virus
• attenuated vaccine
• classical reassortment
• assessment

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Additional information

Funding

This study is supported by the International Cooperation Project (2011DFR30420); Scientific Research Projects of Health Care (200802023); National 863 Program (2012AA02A404); National Science and Technology Major Project (2013ZX10004003-003-002), and Innovation team in Yunnan Province (2015HC027); Medical Science and Technology Innovation Project of Chinese Academy of Medical Sciences (2016-I2M-3-026).