5.4.2　RNA Vaccine

RNA vaccines are the alternative method to DNA vaccines.It directly injects the messenger RNA(mRNA) into the host to conduct the immune response, which is safer than DNA vaccine because it does not come into the nucleus.However, due to instability and short half-life of mRNA, the development of RNA vaccines used to fall behind that of DNA vaccines.Lately, with the progress of stabilization techniques, RNA vaccines have been developed [30].Differences of RNA vaccines from DNA vaccines are easy to be degraded and less likely to cause serious autoimmune diseases and other side effects.Just for this reason, RNA vaccines often need to be used with stabilizers,such as liposomes and protamine [31].RNA vaccination is often conducted in company with some agents like protamines or liposomes to increase immune response.CureVac also developed a self-adjuvanted RNA vaccine called CV9103 for prostate cancer.The result of a phase I/IIa study showed that most of the enrolled patients achieved an immune response [32].Researchers inserted Semliki Forest virus RNA into a vector containing antigen to generate self-replicating RNA vaccine,which can effectively promote the generation of antigen-specific antibodies and CD8+ T-cell response to a certain extent [33].RNA cancer vaccines for melanoma and renal cell carcinoma only reached preclinical study.(https://www.daowen.com)