A rationally designed cancer vaccine based on NIR-II fluorescence image-guided light-triggered remote control of antigen cross-presentation and autophagy

Cancer vaccines represent a promising immunotherapeutic treatment modality. The promotion of cross-presentation of extracellular tumor-associated antigens on the major histocompatibility complex (MHC) class I molecules and dendritic cell maturation at the appropriate time and place is crucial for cancer vaccines to prime cytolytic T cell response with reduced side effects. Current vaccination strategies, however, are not able to achieve the spatiotemporal control of antigen cross-presentation. Here, we report a liposomal vaccine loading the second near-infrared window (NIR-II, 1000-1700 nm) fluorophore BPBBT with an efficient photothermal conversion effect that offers an NIR-light-triggered endolysosomal escape under the imaging guidance. The NIR-II image-guided vaccination strategy specifically controls the cytosolic delivery of antigens for cross-presentation in the draining lymph nodes (DLNs). Moreover, the photothermally induced endolysosomal rupture initiates autophagy. We also find that the adjuvant simvastatin acts as an autophagy activator through inhibiting the PI3K/AKT/mTOR pathway. The light-induced autophagy in the DLNs together with simvastatin treatment cooperatively increase MHC class II expression by activating autophagy machinery for dendritic cell maturation. This study presents a paradigm of NIR-II image-guided light-triggered vaccination. The approach for remote control of antigen cross-presentation and autophagy represents a new strategy for vaccine development.

Prolonged expression of MHC class I - peptide expression in bone marrow derived retrovirus transfected matured dendritic cells by continuous centrifugation in the presence of IL-4.

Background & objectives: Dendritic cells (DCs) are potent antigen presenting cells which proceed from immature to a mature stage during their differentiation. There are several methods of obtaining long lasting mature antigen expressing DCs and different methods show different levels of antigen expressions. We investigated bone marrow derived DCs for the degree of maturation and genetically engineered antigen presentation in the presence of interleukin-4 (IL-4) as a maturity enhancer. Methods: DCs and transfected retrovirus were cultured together in the presence of granulocyte-macrophage colony stimulating factor (GMCSF)-IL4, GMCSF +IL4, lipopolysaccharide (LPS). B 7.1, B7.2 and CD11c were measured by the degree of immune fluorescence using enhanced green fluorescent protein (EGFP) shuttled retrovirus transfected antigen. Degree of MHC class I molecule with antigen presentation of antigen was also evaluated by fluorescence activated cell sorting. The antigen presenting capacity of transfected DCs was investigated. Bone marrow DCs were generated in the presence of GMCSF and IL-4 in vitro. Dividing bone marrow cells were infected with EGFP shuttled retrovirus expressing SSP2 by prolonged centrifugation for three consecutive days from day 5, 6 and 7 and continued to culture in the presence of GMSCF and IL-4 until day 8. Results: IL-4 as a cytokine increased the maturation of retrovirus transfected DCs by high expression of B 7-1 and B 7-2. Also, IL-4 induced DC enhanced by the prolonged centrifugation and it was shown by increased antigen presentation of these dendric cells as antigen presenting cell (APC). Cytolytic effects were significantly higher in cytotoxic T cell response (CTLs) mixed with transfected DCs than CTLs mixed with pulsed DCs. Interpretation & conclusions: There was an enhanced antigen presentation by prolonged expression of antigen loaded MHC class I receptors in DCs in the presence of IL-4 by prolonged centrifugation.

The effects of transforming growth factor β2 and prostaglandin E2 secreted by murine corneal stroma cells on maturating procedure of dendritic cells / 中华实验眼科杂志

Background Researches demonstrated that dendritic cells(DCs) are uniformly immature in the central cornea but mature in the peripheral region of cornea.So an important question is which factor impact the maturation of DCs,especially in terms of corneal transplant rejection and the known roles of DCs in the development and persistence of some corneal diseases.Objective This study aimed to examine whether corneal stroma cells (CSCs) inhibit DCs maturation through secreting transforming growth factor beta 2 (TGF-β2) and prostaglandin E2 (PGE2).Methods DCs,T cells and CSCs were isolated and cultured from clean BALB/c and C57BL/6 mice.The level of PGE2 and TGF-β2in CSCs culture supernatant and the fresh RPMI 1640 medium were then analyzed by enzyme linked immunosorbent assay (ELISA).During the DCs maturation stage,the neutralizing TGF-β2 antibody and the EP2 receptor antagonist AH6809 were added in the CSCs culture supernatant respectively.According to the different treatment,cultured cells were assigned to different groups as follows:control group,CSCs culture supernatant group,AH6809 group,TGF-β2 antibody group,AH6809 +TGF-β2 antibody group.Subsequently,the cellular surface markers for DCs,including CD11c,CD80,CD86,and MHC- Ⅱ,were analyzed by flow cytometry.The capability of stimulating the proliferation of T lymphocytes was evaluated by allogeneic mixed lymphocyte reactions,and the function of endocytosis was assessed by fluorescein isothiocyanate-dextran(FITC) uptake.Results The data of ELISA showed a higher concentration of TGF-β2 and PGE2 in murine CSCs culture supernatant than in the fresh RPMI 1640 medium.Compared with the CSCs culture supernatant group,the expression of CD80,CD86,and MHC- Ⅱ was up-regulated ( P ＜ 0.05 ),the expression of dextran was down-regulated ( P ＜ 0.05 ),and the stimulate index was increased( P＜ 0.05 ) in the TGF-β2 antibody group; the expression of CD86,and MHC-Ⅱ was up-regulated (P＜0.05),the expression of dextran was down-regulated ( F =13.740,P =0.006 ),and the stimulate index was increased(P＜0.05) in the AH6809 group;the expression of MHC-Ⅱ was up-regulated and the stimulate index was increased with statistical difference in interaction(P＜0.05 ) in the AH6809+TGF-β2 antibody group.Compared with the control group,the expression of CD80 and CD86,and the stimulate index was still lower(P＜0.05 ).Conclusions TGF-β2 and PGE2 contribute to the inhibitory effects on DCs maturation mediated by murine CSCs in vitro and further have additive effect on the immunosuppression of DCs.