Study On Nano Adjuvant Combined With Immune Checkpoint Inhibitors In The Treatment Of Tumor

To explore the adjuvant effect of Cp G-nano adjuvant on the activation of dendritic cells(DC)in vitro and the antitumor effect of Cp G-nano adjuvant combined with checkpoint inhibitor anti-PD-1 in mouse melanoma model.Adjuvant Cp G was encapsulated inβ-glucan based nanoparticle(CNP)to generate nano-adjuvant.The dendritic cells from bone marrow of mice were divided into four groups for immune-adjuvant treatment:PBS immune control group,β-glucan nano carrier(NP)group,CPG immune group and CNP group.DC maturation was analyzed by flow cytometry,and the expression of related cytokines in DC culture supernatant was analyzed by ELISA.Melanoma B16F10 cells were inoculated subcutaneously on the right hind limb of C57BL/6N mice to establish tumor model.When the tumor size was about 50 mm~3,60 mice with relatively consistent tumor size were selected and divided into 6 groups:PBS control group,anti-PD-1 group,NP+anti-PD-1 group,CPG+anti-PD-1 group,CNP+anti-PD-1 group,and the sixth group was CNP+anti-PD-1+anti-CD8 group to explore the role therapy of CD8~+T cells in combined immunotherapy.The tumor volume was measured every two days.The blood was collected three days after the last administration.The IFN-γconcentration in the plasma was measured by ELISA.The tumor and spleen were separated after euthanasia.The proportion of infiltrative T lymphocytes in tumor and T cells in the spleen were measured by flow cytometry.The experimental results showed that CNP adjuvant could effectively stimulate DC maturation and promote IL-6,IL-12,TNF-αsecretion.The mice inoculated with anti-PD-1 also showed good antitumor effect in vivo.the IFN-γcontent in plasma and tumor infiltrating T lymphocytes in mice were significantly increased.CD8~+T cell deletion experiment showed that CD8~+T cells play an important role in tumor immune therapy.The nano-adjuvant CNP constructed in this study is able to effectively activate DC,and had a synergistic antitumor effect combined with anti-PD-1 in vivo,significantly improve tumor microenvironment.