Heterologous expression of recombinant dengue virus C-prM-E structural antigens from all four serotypes in the red microalga Porphyridium purpureum

The dengue virus (DENV) remains a significant global health threat, and the currently available vaccines exhibit concerns regarding safety, efficacy, and cost-effectiveness. Microalgae represent an innovative method for producing proteins that do not occur naturally. They are Generally Recognized As Safe (GRAS), easily scalable, and capable of inducing post-translational modifications in eukaryotes. This study illustrates the effective heterologous expression of recombinant dengue virus capsid–premembrane–envelope (C-prM-E) structural antigen constructs representing all four DENV serotypes (DV1–DV4) in the red microalga Porphyridium purpureum through Agrobacterium tumefaciens -mediated transformation. Gene constructs containing capsid-premembrane-envelope (CprME) polyprotein fragments with C-terminal epitope tags were cloned into pCAMBIA1301 vectors and subsequently introduced into P. purpureum . PCR amplification confirmed the successful chromosomal integration of all four serotype constructs, yielding the anticipated 2.5-kb amplicons. The SDS-PAGE analysis revealed protein bands at around 85 kDa, consistent with the expected molecular weight of the processed CprME-derived proteins. We employed both anti-DENV-2 and anti-FLAG antibodies in a western blot assay to demonstrate that the recombinant antigens were identical and interacted with the immune system across all serotypes. These findings indicate that P. purpureum is an effective system for expressing DENV antigens, paving the path for the development of cost-effective, plant-derived dengue vaccine candidates. This microalgal platform may facilitate the large-scale production of tetravalent dengue vaccines, particularly in regions where dengue is prevalent and resources are scarce.