Fig. 4: An NP mutant with the CpG1826 but without the bacterial RNA binding activity as a target for universal influenza vaccines. | npj Vaccines

Fig. 4: An NP mutant with the CpG1826 but without the bacterial RNA binding activity as a target for universal influenza vaccines.

From: Addressing unexpected bacterial RNA safety concerns of E. coli produced influenza NP through CpG loaded mutant

Fig. 4

A Non-denaturing PAGE showed that the NP mutant (arginine mutates into glycine) lose the E. coli RNA binding activity. The RNase A-treated (NP-Tx) and untreated (NP) wild-type recombinant NP proteins were used as controls. The gel was stained with EB. B Non-denaturing PAGE showed that the recombinant NPmut proteins could bind CpG1826 (highlighted in red box). NP, NP-Tx, and 3M2e were used as controls. C, D Co-delivery of CpG1826 enhanced the immune responses against NPmut. Mice were immunized as shown in Fig. 1A. NP-specific total IgG, IgG1 and IgG2a in sera (C) (n = 5), and NP-specific IgG and IgA in BALF (D) (n = 3) were measured by ELISA. Data are presented as mean ± S.D. **, ***, and **** indicate p < 0.01, p < 0.001, and P < 0.0001, respectively (ANOVA). Two weeks after the last immunization, mice were challenged with 5 × LD50 of A/PR/8/34. Body weight and survival rate of mice (n = 5) were monitored daily for 14 days (E). The statistical significance of survival curves was determined by the log-rank (Mantel-Cox) test. * between PBS and NP, ns between NP, NP-Tx/CpG1826 and NPmut/CpG1826. Lungs (n = 3) were collected 4 days after challenge for histopathologic analysis (F). Scale bars, 200 µm.

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