Journal: Cell Reports Medicine

Article Title: Preclinical evaluation of an mRNA vaccine developed from the first human isolate of bovine H5N1

doi: 10.1016/j.xcrm.2026.102702

Figure Lengend Snippet: Comparison of vaccine efficacy between H5 Texas Mut vaccine and H5 Ast20 Mut vaccine in mice (A) Schematic of cleavage-defective mutant (Mut) HA mRNA vaccines. (B) Western blotting analysis of HA protein expression in transfected BHK-21 cells. Cells were transfected with varying doses (50, 100, 200, and 500 ng/μL) of Texas Mut or Ast20 Mut mRNA. (C) Mice were vaccinated (i.m.) with 1 or 5 μg Texas/Ast20 mRNA-LNP (SM102) encoding Mut HA or placebo using in a prime-boost schedule with an interval of 4 weeks. Blood samples ( n = 8) were collected from mice 2 weeks after prime and boost. Binding IgG of serum, reactive to the Texas HA protein, was measured by ELISA. Titers of placebo group were below detection limit. (D) 50% neutralization titers of pseudotyped virus (A/Texas/37/2024) in serum collected 2 weeks post-boost (week 6). Titers of placebo group were below detection limit. (E and F) Binding IgG of 1 μg Texas vaccine group (E) and Ast20 vaccine group (F) was measured by ELISA, reactive to the HA of clade 1 virus (A/Viet Nam/1203/2004), clade 2.1.3.2 virus (A/Indonesia/5/2005), clade 2.2 virus (A/bar-headed goose/Qinghai/5/2005), clade 2.3.2.1a virus (A/Hubei/1/2010), clade 2.3.4 virus (A/Anhui/1/2005), clade 2.3.4.4b virus (A/Astrakhan/3212/2020), and clade 2.3.4.4b virus (A/Texas/37/2024). (G) Radar chart of broad-binding IgG levels elicited by 1 μg Texas vaccine and Ast20 vaccine. (H) Vaccination schedule. Mice were vaccinated (i.m.) with 1 or 5 μg mRNA-LNP (SM102) encoding Texas HA-Mut, Ast20 HA-Mut, or placebo. Four weeks post-vaccination (week 4), mice were challenged with 50 × LD 50 of A/ostrich/China/HB/2024. Virus load of organs in vaccinated mice 1, 3, 5 days post-infection determined using plaque assays on MDCK cells. (I–L) Virus load of lung (I), heart (J), kidney (K), and brain (L). The dashed horizontal line indicates the assay limit of detection. Data are presented as the mean ± SD; p values are analyzed with t test (∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001) (C–L). ∗/∗∗∗ (E and F) indicates significant differences between other HA proteins and Texas (E) or Ast20 (F) protein. ∗ (E and F) indicates significant differences between other HA proteins and Texas (E) or Ast20 (F) protein. ∗ (I–L) indicates significant differences between placebo and vaccination groups in the same day.

Article Snippet: HA recombinant protein of A/Indonesia/5/2005 , Synthesized from Novoprotein , N/A.

Techniques: Comparison, Mutagenesis, Vaccines, Western Blot, Expressing, Transfection, Binding Assay, Enzyme-linked Immunosorbent Assay, Neutralization, Virus, Infection