Journal: bioRxiv

Article Title: Rational design of respiratory syncytial virus dimeric F-subunit vaccines in protein and mRNA forms

doi: 10.1101/2025.05.31.655981

Figure Lengend Snippet: (A) Schematic diagram and design rationale of monomer A. The design of monomer A was outlined (top). Substitutions unique to monomer A and DS2 are labeled in black and gray, respectively. Substitutions shared among DS-Cav1, DS2, and monomer A are colored in red, and those shared between DS2 and monomer A are colored in blue. The dashed squares indicated the deleted residues. In the pre-F structure (PDB: 5k6i), Epitope I, II, III, IV, V, and Ø were labeled in magenta, green, purple, red, yellow, and blue, respectively and their neutralizing sensitivities are indicated. (B) Binding affinities of monomer A (top) and scDimer AA (bottom) with MAbs targeting six epitopes. Actual and fitted curves were represented by red and black lines, respectively. K D values were listed as mean ± SD of three experiments. (C) Endpoint titers of immunized antigen-binding IgG in murine sera were measured by ELISA. Groups of mice (n=4∼5) were intramuscularly immunized with 3 or 10 µg of monomer A or scDimer AA at 0, 3, and 6 weeks with Alhydrogel ® adjuvant. Serum samples were collected on day 56 (two weeks after the 3 rd immunization) and subjected for ELISA test. (D) Neutralization of RSV A2 strain in murine sera on day 56 was assessed. (E) Design of scDimer AA. Two truncated monomers A were tandemly linked, with the latter one starting at N27 residue. (F) Crystal structure of scDimer AA, with epitopes labeled as in panel A. Dotted lines represented areas with uncharacterized structures due to the flexibility of the regions. In (C) and (D), dotted lines indicated the lower limit of detection (LLD). Any value less than the LLD was assigned a value of 1⁄2 the LLD. Data were derived from two technical replicates of a single experiment, with bars indicating mean ± SD. P values were determined using Two-way ANOVA (ns indicated P > 0⋅05; * indicated P < 0⋅05; ** indicated P < 0⋅01, *** indicated P < 0⋅001, **** indicated P < 0⋅0001).

Article Snippet: DS-Cav1, a representative pre-F stabilized by introducing a disulfide bond and two cavity-filling substitutions, is adopted in the approved GSK protein-based vaccine, Arexvy., An enhanced version, DS2, with additional disulfide bonds and substitutions, was also adopted in Moderna’s licensed mRNA vaccine (mRNA-1345, mRESVIA).

Techniques: Labeling, Binding Assay, Enzyme-linked Immunosorbent Assay, Adjuvant, Neutralization, Residue, Derivative Assay