Establishment of a Carrot Cell Plant Growth Regulators-free System to Produce a Low-Cost Vaccine Candidate

Parkinson's disease is characterized by an abnormal accumulation of alpha synuclein (<i>α</i>-syn) in different regions of the central nervous system. At present, only palliative pharmacological treatments are available for Parkinson´s disease. Immunotherapy is considered an alternative to treat Parkinson's disease, and plants are a convenient alternative platform for biopharmaceutical production. When compared to other systems, plants are particularly attractive because they offer cost-effectiveness, large-scale production, and enhanced safety. Therefore, this study aimed to establish a carrot cell suspension culture for the production of cLTB-Syn, a vaccine candidate against Parkinson's disease. The convenience of MS medium optimization was demonstrated. Transgenic callus cultures were maintained and adapted on solid MSU9 medium without phytohormones, followed by growth kinetics in suspension cultures. The maximum biomass yield was 15.8 ± 0.35 g/L DW at 14 days of culture, with a growth rate of µ = 0.1034/d and td = 6.7 days. The cLTB-Syn protein production reached a maximum value of 2.62 ± 0.03 µg/g DW, representing a 1.6-fold increase over the initial culture time. Finally, the presence of the transgene was confirmed by PCR, and the integrity of cLTB-Syn protein was determined by dot blot assays. This study presents evidence of a promising system for a toxin-free biopharmaceutical production, which has the potential to be scaled up for large manufacturing, at a low cost.