Human MxA protein induced by type I and III interferons is an important innate immunity mediator, it shows antiviral activity against a broad spectrum of RNA and DNA viruses. According to the latest data, the MxA protein overexpression increases chemotherapy sensitivity and represents one of the favorable prognostic factors in patients with breast cancer. The exogenous mRNA capable of intracellular MxA protein production not only has the potential for treatment of viral respiratory infection, but also can become an important fundamental research tool. The study aimed to construct and produce the exogenous mRNA encoding the functional human cytoplasmic MxA protein by in vitro transcription (IVT); to study its translational properties; to assess and identify the patterns of the expression of some interferon system genes in response to introduction of this exogenous mRNA into cells. As a result of the study, the exogenous mRNAs capable of effective translation (up to 20 ng/mL of protein from 100 ng of mRNA per well of the 96-well plate) in the eukaryotic cell systems were successfully constructed and produced by IVT (in the amount of up to 200 µg); diffuse distribution of the MxA protein in the MDCK cells was confirmed; significant changes in the expression of the interferon-stimulated genes, such as OAS1, PKR (EIF2AK2), MDA5, RIG-I, were revealed. Our further research will be focused on assessing the developed exogenous mRNAs’ therapeutic potential against influenza A and B viruses, respiratory syncytial virus, and coronavirus SARS-CoV-2.