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. Author manuscript; available in PMC: 2023 May 12.
Published in final edited form as: Sci Transl Med. 2022 Jan 26;14(629):eabj5305. doi: 10.1126/scitranslmed.abj5305

Figure 2. AH:CpG adjuvant formulation elicited a robust anti-RBD response in aged mice.

Figure 2.

Aged, 14-month-old BALB/c mice were immunized intramuscularly on Days 0, 14, and 28 with 10 μg of monomeric SARS-CoV-2 RBD protein with indicated adjuvants. Each PRR agonist was formulated with aluminum hydroxide (AH). Serum samples were collected and analyzed on day 28 prior to the 2nd boost (A to F), and day 42 (G to L). (A, G) Anti-RBD IgG, (B, H) IgG1, (C, I) IgG2a, (D, J) IgG2a:IgG1 ratio, (E, K) hACE2-RBD inhibition rate, and (F, L) neutralizing titers were assessed. n=9 to 10 per group. (M) Splenocytes were collected 2 weeks after the final immunization and stimulated with a SARS-CoV 2 spike peptide pool in the presence of anti-CD28 antibody. After 24 (for IL-2 and IL-4) and 96 (for IFN-γ) hours, supernatants were harvested and cytokine concentrations were measured by ELISA. n=4 to 5 per group. Data were log-transformed and analyzed by one-way ANOVAs followed by post-hoc Tukey’s test for multiple comparisons. *P <0.05, **P <0.01, ***P <0.001, **** P <0.0001. Blue and red colored asterisks indicate comparisons to RBD and AH-adjuvanted RBD groups, respectively. Box-and-whisker plots represent the minimum, first quartile, median, third quartile, and maximum value. LLD, lower limit of detection.