Fig. 7.
In vivo therapeutic efficacy of PBAE mRNA nanoparticle (NP) vaccination in the MC38-OVA mouse colon carcinoma model. (A) 1 × 106 MC38-OVA cells were inoculated subcutaneously in the right flank of C57BL/6J mice on day 0, and R18D NPs encapsulating luciferase-encoding mRNA or OVA-encoding mRNA (10 μg mRNA/mouse) and CpG (2.5 μg/mouse) were administered intravenously on days 9 and 14 (n = 7 to 8 mice/group). Then, 200 μg of aPD-1 was injected intraperitoneally on day 10. Tumor growth measurements showing the in vivo therapeutic effects between the treatment groups. Significance indicates comparison of the aPD-1 + mOVA/CpG NP treatment group to the aPD-1 group (black) or aPD-1 + mLuc/CpG NP group (pink). (B) Mice were euthanized once tumors reached 200 mm2, and survival curves are shown. (C) Four mice were randomly selected from each group to be bled on day 21 postinoculation, and the percent of OVA-specific CD8+ T cells out of total CD8+ T cells in the blood was assessed using H2Kb SIINFEKL tetramer staining. (D) The percent of CD8+ T cells out of total CD3+ T cells in blood is shown. (E) Representative flow cytometry plots showing BV421 H2Kb SIINFEKL tetramer staining in CD3+ CD8+ cells in all groups. Error bars represent SEM.