03 Jun 2019

Theme-based Research Scheme seminars with Sophie Valkenburg and (HKU-Pasteur) and Katherine Kedzierska (University of Melbourne, The Peter Doherty Institute)

Sophie Valkenburg, team leader at HKU-Pasteur, and Katherine Kedzierska, Department of Microbiology & Immunology, University of Melbourne, The Peter Doherty Institute for Infection & Immunity, will give seminars as part of the Theme-based Research Scheme on Viral, Host and Environmental Determinants of Influenza Virus Transmission and Pathogenesis. 

Date: 12 June 2019 (Wed)
Time:  11:00-12:30
Venue: Seminar Room 3, G/F The HKJC Bldg for Interdisciplinary Research
5 Sassoon Road, HK 
>>> Immune correlates in influenza vaccination and infection
By Dr Sophie Valkenburg
Inactivated influenza vaccines (IIV) are the most widely used vaccines in the world due to seasonal epidemics and annual updates to vaccine strains. These vaccines account for over 500 million doses costing over $5 billion USD. Older adults experience the highest mortality and are prioritised for seasonal vaccination yet can have the lowest vaccine efficacy. What happens to our immune system when we are repeatedly vaccinated for influenza, and which vaccine is the best option?
The only standardised and widely accepted immune correlate of protection for influenza vaccine mediated protection is, Haemagglutinin inhibition antibodies (HAI). Yet HAI gives an incomplete picture to vaccine responses and their immunogenicity, whilst next generation influenza vaccines need alternate protective immune correlates defined. In a randomised control immunogenicity trial of older adults, in close collaboration with the CDC and Professor Ben Cowling’s team, we are deciphering immune correlates for repeated and enhanced vaccines in older adults in Hong Kong. Our focus is vaccine immunogenicity for antibody quality and cellular responses.
We recently reported that one round of twice-annual vaccination resulted in elevated HAI titers in the second round of vaccination, but reduced H3N2-specific influenza-specific CD4+ T cell responses. In further studies we have assessed vaccination effects on recruitment of T follicular helper cell and plasma blast B cell responses, which are important drivers for high quality antibody responses. We further characterised influenza-specific antibody quality by IgG sub-classes associated with ADCC effector functions. Enhanced influenza vaccines were also assessed in a mouse model of vaccination and lethal influenza challenge to determine vaccine superiority. We found a particular advantage for adjuvanted influenza vaccines for both antibodies and cellular responses in the mouse model.
>>> Universal CD8+T Cell Immunity to Influenza Viruses
By Professor Katherine Kedzierska
Professor Kedzierska’s research is centered on understanding key factors driving generation of optimal immunity in viral infections, especially pandemic, seasonal and newly emerged influenza viruses such as A/H7N9. Her work spans basic research from mouse experiments to human immunity, through to clinical settings, with a particular focus on understanding universal cross-strain protective T cell immunity to influenza viruses. Her studies aim to identify key correlates of severe and fatal influenza disease in high-risk groups, including young children, the elderly and Indigenous Australians.