Marcin Pyrski
Institute of Plant Genetics - Polish Academy of Sciences, Poland
Title: Oral booster vaccine against hepatitis B in the form of low-dosed lyophilised plant tissue bearing S-HBsAg VLPs
Biography
Biography: Marcin Pyrski
Abstract
The continued HBV high prevalence coupled with deficiencies in vaccination programmes stimulate research on a new type
of vaccines. Potential orally administered plant-based vaccine is highly attractive regarding efficacy, cost-effectiveness and
availability of mass hepatitis B prevention. Freeze-dried oral formulations facilitate elimination of complex purification steps, size
reduction and better stability during storage, as well as ensure controlled administration regime in minimised medical facilities.
Micropropagation of lettuce expressing S-HBsAg was optimised to provide repeatable uniform feedstock for plant-derived oral
vaccine manufacturing. Lyophilisation protocol facilitating successful processing of lettuce leaf tissue containing S-HBsAg assembled
into VLPs (Virus-Like Particles) was developed. Several drying profiles and excipients as well as effects of freezing rate and postprocess
residual moisture were analysed. The profile of 20ºC for 20 h for primary and 22ºC for 2 h for secondary drying as well as
sucrose proved the most efficient stabilisation of S-HBsAg during freeze-drying. The process was highly reproducible (86-97%), and
provided a product with VLP content up to 200 μg/g DW. Atmosphere of nitrogen proved to preserve S-HBsAg VLPs for minimum
one year at temperatures up to 37°C. Low-dosed (5-200 ng) preparation used as oral booster vaccine elicited anti-HBs response in
animals at level of commercial injection vaccine (around 1000 mIU/ml). As a result, a plant-derived semi-product with good longterm
stability and immunogenicity of S-HBsAg was obtained for the definite formulation of oral booster vaccine against HBV.