The Preparation And Evaluation Of Tumor Associated Antigen Polypeptide Loaded Poly (?-amino Ester) Nano-Vaccines

Objectives:On account of development of cancer immunotherapy in the past 20years,anti-cancer vaccines have received more and more attention.Anti-tumor vaccine based on dendritic cells(DCs)manufactured by nanotechnology is an effective method to stimulate specific immune response in vivo,which has been widely studied domestically and abroad in recent years.Poly(?-amino esters)(PBAE),a cationic polymer,is a potential antigen carrier with characteristics of convenient synthesis,easy modification,biodegradability and pH sensitivity which can load and protect antigens efficiently,and deliver antigens to DCs cells for subsequent recognition,presentation and stimulation of immune response eliciting specific anti-tumor immune efficacy.Methods:In this study,we synthesized stearamine(SA)containing poly(?-amino esters)(PBAE-S)through classical Michael addition reaction.In order to increase targeting ability of T/M@mPS nano-vaccines to DCs,mannose was connected with terminal groups of PBAE.The polymer structure and nanoparticle morphology were investigated by ~1H-Nuclear Magnetic Resonance(~1H-NMR),Fourier Transform Infrared Spectroscopy(FTIR),Dynamic Light Scattering(DLS),Transmission Electron Microscope(TEM)and other methods.Meanwhile,in-vivo imaging system of small animals,flow cytometry and enzyme-linked immunosorbent assay(ELISA)were used to verify the targeting ability of T/M@mPS nano-vaccines and stimulating ability of anti-tumor immune response in vivo or in vitro.To further boost the efficacy of nano-vaccines,we combined PBAE nano-vaccines with PD-L1 antagonist in the mouse melanoma model to evaluate the prophylactic and immune efficacy of the synergistic therapy.Results:PBAE-S copolymer can efficiently encapsulate tumor-associated antigen polypeptide Trp-2,and form stable nanoparticles with size of about 150 nm.Modification of mannose endowed nano-vaccines a potent targeting property in vitro and in vivo,and can increase the maturation of DCs,thereby enhancing the proliferation and differentiation of killer T cells in vivo.After combination of PD-L1 antagonist therapy,nano-vaccines showed stronger anti-tumor immune efficacy.Conclusions:As a cationic polymer carrier with easily tunable structure,PBAE polymers can promote the delivery of antigen polypeptide and stimulate specific immune response in vivo.So it has promising prospects in broad application of peptide based vaccine construction,which provides a new strategy for cancer immunotherapy.