The success of COVID-19 mRNA vaccines highlights the transformative potential of mRNA technology. Current mRNA vaccine development involves complex steps, including plasmid construction, RNA transcription, 5' capping, poly(A) tailing, and lipid nanoparticle encapsulation, yet challenges in vaccine accessibility persist. Here, we present an innovative mRNA platform leveraging the self-assembly capabilities of the MS2 bacteriophage viral capsid protein (VCP). A dual-promoter plasmid has been designed where one promoter drives VCP expression while the other transcribes target RNA containing pac sites, enabling rapid mRNA self-assembly in Escherichia coli (E. coli). Using an ovalbumin (OVA)-based tumor model, we validate the efficacy of this system. Tumor growth is significantly inhibited, accompanied by robust immune activation. Flow cytometry analyses reveal increased frequencies of OVA-specific CD8