The Preparation Of Nano-tumor Vaccine And Its Anti-tumor Effect

As a promising approach to cancer immunotherapy,cancer vaccines are emerging as powerful weapons for the treatment of cancer.Nanotechnology has increasingly played a significant role in vaccine development.Several nanoparticle carriers,such as liposomes,polymeric nanoparticles,and inorganic nanoparticles,have been shown to possess significant potential as vaccine delivery systems and immunostimulatory adjuvants.However,despite the progress in this field,the successful immunotherapy of tumors with cancer vaccines is still a major challenge.Another challenging aspect in the development of effective strategies for cancer vaccines is to engender cellular immunity and antigen-specific cytotoxic T-lymphocyte(CTL)responses,which are important for the control of cancer.In this study,we developed three novel formulations of nanoparticles-based vaccine for cancer immunotherapys.Our objectives were to investigate whether the use of these prepared nanovaccines facilitates the cytosolic delivery of antigens and hence promotes MHC-I-restricted CD8+ T-cell responses and to evaluate these resultant antigen-specific immune responses.The first part:An indocyanine green(ICG)-antigen nanovaccine achieving cytoplasmic delivery of antigens by photochemical internalization under laser irradiation was prepared.In our design,model antigen OVA conjugated with a photosensitizing molecule,ICG,would self assemble in aqueous solution via strong intermolecular hydrophobic interactions between ICG and OVA.ROS can be generated by ICG to disrupt of the membranes of endo/lysosomes via photooxidative damage with NIR laser irradiation,which helps to release antigen into the cytosol efficiently,thereby robustly enhancing proteasome activity and antigen presentation of the MHC-I pathway.The anti-tumor studies of E.G7-OVA tumor-bearing mice showed that ICG-OVA nanovaccine inhibite tumor growth,increase the proportion of CD3+CD8+ T cells in the spleen and tumors,induce amount of memory CD8+ T cells.The second part:In this study,HA-OVA-AuNPs nanoparticles were successfully developed as a nanovaccine and evaluated for tumor immunity.Efficient cellular uptake via receptor-mediated internalization was obtained by modifying the surface of AuNPs with HA.Subsequently,cytosolic antigen delivery was permitted through a photothermally controlled process of local heat-mediated endo/lysosome disruption by laser irradiation.Finally,ROS production triggered by endo/lysosome rupture enhanced proteasome activity and downstream MHC-I antigen presentation.The anti-tumor study of E.G7-OVA tumor-bearing mice showed that HA-OVA-AuNPs vaccine increase the proportion of CD3+CD8+ T cells in lymph nodes,promote the proliferation and activation of antigen-specific CD8+ T cells,the immune response to CTL,increase the proportion of INF-?+CD8+ T cells,inhibited tumor growth effectively and prolonged the survival time of tumor-bearing mice.The third part:A novel formulation of aluminum-based adjuvant by preparing AlO(OH)modified grapheme oxide(GO)(GO-AlO(OH))nanosheet,which,aside from maintaining the induction of humoral immune response by AlO(OH),could further enhance the cellular immune response by GO,is described.The preparation process of the nano-adjuvant is simple and the antigen-loaded nanovaccine(GO-Al-OVA)can be obtained by co-incubation with the model antigen OVA.Antigen-loaded GO-AlO(OH)nanosheet enhance cellular uptake and achieve cytoplasmic delivery of antigen,promote DC maturation.GO-Al-OVA nanovaccine immune mice show that the GO-Al-OVA nanovaccine was able to induce IgG2a-associated Th1-type immune response and IgG1-associated Th2-type immune response.The anti-tumor effect of E.G7-OVA tumor-bearing mice showe that the GO-Al-OVA nanovaccine induce the production of antigen-specific IgG antibody,increase the proportion of CD3+CD8+ T cells in the spleen,induce CTL immune response,and promoted antigen specificity.CD8+T cells proliferate,thereby inhibit tumor growth and prolong survival time of mice.In addition,GO-AlO(OH)nanosheet is capable of loading B16 tumor cell lysate(TCL),which are mixed to prepare a GO-Al-TCL nanovaccine.The results of anti-tumor studies of B16 tumor-bearing mice showed that the GO-Al-TCL nanovaccine can promote the production of antigen-specific IgG,promote the proliferation and differentiation of CD 8+T cells,induce CTL immune responses,thereby inhibit tumor growth,and prolong survival time of mice.In addition,GO-Al-TCL nanovaccine inhibit melanoma cells from lung metastasis.In summary,we successfully developed three novel formulations of nanoparticles-based vaccine for cancer immunotherapys.The prepared nanovaccines enhanced cellular uptake and cytosolic release of antigens,promoted DC maturation,thereby elicited higher antigen-specific IgG titers and induced robust antigen-specific CD4+ and CD8+ T-cell responses with antitumor efficacy in vivo.Looking forward,The prepared nanovaccines are promising as effective adjuvants with the powerful ability to elicit cellular immune responses,providing a novel approach for improving cancer immunotherapy efficacy.