| ObjectivemRNA vaccine is formed by mRNA transcribed in vitro and encapsulated by liposome.Compared with traditional inactivated vaccine,it has low production cost,can quickly deal with virus mutation,and does not need to enter the nucleus,showing good biological safety.The development of an mRNA tumor vaccine that can efficiently deliver and stimulate a strong tumor-specific immune response is a great challenge in the field of vaccine development.Here,we construct a novel personalized tumor vaccine composed of core-shell lipid complex(LPP,Lipopolyplex)nanoparticles and mRNA expressing tumor-specific antigen,which can be used in tumor immunotherapy,in order to provide a new idea for the treatment of tumor patients.MethodsIn this study,a personalized mRNA tumor vaccine based on LPP delivery vector was designed.LPP lipid nano-delivery vector could deliver mRNA vaccine to lymph nodes in the body,thus activating tumor-specific immune response and improving the efficacy of anti-tumor therapy.Firstly,fluorescence imaging was used to observe the distribution of LPP-mRNA vaccine in different organs in vivo and in vitro tissues.Secondly,after LPP-mRNA treatment,the antigen uptake of DC was analyzed by flow cytometry,and the ability of T cells to secrete IFN-γ was detected by ELISPOT(enzyme-linked immunospot assay).Finally,in CT26,MC38 and A20 tumor-bearing mouse models,tumor growth,survival time and anti-tumor effect of PD-1 treatment were monitored.Finally,tumor growth and survival were monitored in CT26,MC38 and A20tumor-bearing mouse models.ResultsIn this project,the LPP-mRNA vaccine encapsulated by LPP nano-lipid particles was successfully constructed.In the tumor-bearing mouse model,LPP-mRNA can reach lymph nodes through lymphatic circulation and effectively activate DC 24 hours after inoculation,and promote the uptake of antigen by activated DC.LPP-CT26 mRNA,LPP-MC38 mRNA and LPP-A20 mRNA vaccine encoding 20 neoantigens screened by tumor neoantigen prediction system can effectively activate tumor-specific T cell immune response in corresponding CT26,MC38 and A20 tumor bearing mouse models,and inhibit tumor growth.ConclusionsThe neoantigen tumor vaccine based on LPP lipid nano-delivery vector prepared in this study can deliver tumor-specific neoantigens to antigen presenting cells(APC)and stimulate maturation,induce anti-tumor immune response and inhibit tumor growth in tumor-bearing mice.The vaccine also shows the potential to prevent tumor growth,which can be further enhanced when combined with immune checkpoint inhibitors. |
