Abstract:
After the body is invaded by pathogens, it responds by secreting cytokines, for example, interleukin 6 (IL-6), which activates an intracellular signaling pathway involving JAKs/STAT3 through phosphorylation. However, overexpression of pSTAT-3 can lead to a positive feedback loop of IL-6, causing the release of more cytokines and potentially leading to cytokine storm. Thus, inhibition of IL-6 signaling is another important target for Cytokine storm treatment. Tocilizumab, a humanized IL-6R antibody has been approved for RA treatment. There are several concerns about mammalian cell protein expression systems, such as higher production costs and pathogen contamination risks. Recently, plants have become increasingly popular as an alternative system for recombinant protein expression. Therefore, the purpose of this research is to develop an antibody that targets IL-6 receptor (IL-6R) using Nicotiana benthamiana as an expression system. The HC and LC of the mAb targeting human IL-6 receptor (IL-6R) were constructed using the pBYK2e geminivirus expression vector. The constructs were then transiently co-expressed and investigated the optimal expression conditions in Nicotiana benthamiana. The findings indicate that the optimal conditions for expressing the Anti-IL-6R mAb involve infiltrating plant leaves with Agrobacterium containing HC or LC (each bacterial concentration of OD600 0.2) at a 1:1 ratio (HC:LC) at 5 dpi. The plant-produced Anti-IL6R mAb showed specific binding activity to human recombinant IL-6R protein, with KD value of 1.748 µg/mL. In contrast, the negative control did not bind as expected. Although we have demonstrated the capability and appropriateness of the plant platform for creating this therapeutic antibody, additional in vivo research is crucial to completely understanding the effectiveness of Anti-IL-6R mAb.