Virology & Mycology
Open Access

TLR7 agonist Imiquimod enhances the efficacy of 2009 pandemic H1N1 vaccine in BALB/c mice

2^nd International Conference on Flu

October 31-November 02, 2016 San Francisco, USA

Li Can

The University of Hong Kong, Hong Kong

Posters & Accepted Abstracts: Virol Mycol

Abstract :

TLR ligands, which can directly stimulate immune responses towards antigens, have shown great promise as novel adjuvants in many vaccine studies. Imiquimod, a synthetic TLR7 agonist, could significantly enhance immune responses together with conventional vaccine strategies. Our previous study showed an inactivated 2009 pdm H1N1 vaccine combined with imiquimod (VCI) could elicit immediate immune responses against influenza A (H1N1) pdm09 infection in BALB/c mice as early as 3 days prior to challenge. Survival rate was significantly improved in VCI group. Neutralizing antibody and virusspecific antibody could be detected in mouse sera at day 4in VCI group. We further investigated the mechanisms by which imiquimod enhances the efficacy of vaccine. The results showed that intraperitoneal administration of VCI induced significant amount of monocytes recruitment to the peritoneal cavity; meanwhile peritoneal resident B cells are activated and migrated rapidly to lymphoid organs. We found that B cells in spleen increased and expressed increased surface marker CD86 after 18 hours treatment. B cells in lung also significantly increased rapidly after infection in VCI group compared with untreated mice. Germinal center involved B cells and plasma cells increased in lymph nodes at day 3 p.i. These results indicated imiquimod combined with vaccine may stimulate local B cells activation and enhance the proliferation and differentiation. Finally, the fastacting antibody-based immune responses induced by vaccine combined with imquimod may provide a new strategy facing immediate unpredicted influenza outbreaks. The mechanisms of early B cell activation deserve further study.

Biography :

Li Can has completed her PhD and is currently a Postdoctoral Fellow in the Department of Microbiology, the University of Hong Kong. She mainly researches on vaccine and the pathogenesis of influenza viruses, including pandemic H1N1 virus, H5N1 and H7N9 viruses. She has published several papers during her PhD study.

Email: leecan10@gmail.com