Date: Monday 20 October 2025
Time: 12:00pm - 1:00pm
Venue: Postdoc Centre - 16 Mill Lane
This session includes talks on recombinant human immunoglobulins and transgene expression in marine microalgae from early-career researchers at the Department of Plant Sciences.
Nicotiana benthamiana as a chassis for producing recombinant human IgGs
Konstantina Beritza, Department of Plant Sciences
Abstract:
Plants offer a powerful platform for recombinant protein expression, and have been used for successful production of human immunoglobulins G (IgGs). This offers an enticing alternative to current strategies for production of pharmaceutical antibodies. However, degradation of recombinant proteins by endogenous proteases causes severe yield losses and this minimises plants’ potential as viable production platforms. To tackle this issue, we examined the stability of antiviral human IgGs in the extracellular space or apoplast of Nicotiana benthamiana. Subtilase SBT5.2 was identified as the main apoplastic protease cleaving the HIV-neutralising antibody 2F5, though susceptibility varied among anti-viral antibodies. Less than 5% of IgGs reached the apoplast, suggesting retention and processing within other compartments. Redirecting antibodies to the endoplasmic reticulum substantially increased accumulation, up to ninefold. Finally, we explored the accumulation of IgGs in a synthetically extended ER formation, paving the way to more accurate ways for controlled compartmentation of recombinant proteins upon heterologous production. Together, these findings show that protease activity and subcellular targeting strongly influence antibody stability in plants. Thus, modulating these factors could improve plants as platforms for antibody production.
Insights into transgene expression and silencing in a marine microalga
Caroline Faessler, Department of Plant Sciences
Abstract:
My talk will summarise a few findings from my PhD research on metabolic engineering in the marine diatom Phaeodactylum tricornutum. Stable transgene expression is a key challenge when using P. tricornutum as a biotechnological platform. I examined how regulatory elements influence expression and monitored the long-term stability of transgene expression. Promoter choice strongly affected expression levels, while introns and codon optimisation had little impact. Over time, transgene expression declined, especially in metabolically active constructs and under certain subculturing conditions. Preliminary results point to epigenetic changes as a possible cause of silencing, though the exact mechanisms remain unclear. These findings provide new insights into transgene silencing in P. tricornutum and highlight potential strategies to improve the reliability of transgene expression in diatom biotechnology.