Fig. 3: MARV and RAVV vaccines generate different proportions of binding antibodies targeting GP regions.

A Schematic of truncated GP forms. Blue lines represent deleted regions. SP, signal peptide (white); RBD, receptor binding domain (gold); GC, glycan cap (blue); MLD, mucin-like domain (gray); W, wing (purple); STEM, GP2 lacking the transmembrane domain (TM, green). GPΔTM GP ectodomain, GPΔmuc GP mucin-deleted ectodomains, GPcl proteolytically-cleaved GP, GPΔmucΔw wing-deleted RAVV GPΔmuc. Red line indicates the furin cleavage site. B, D, E Day 54 MARV (green) and RAVV (blue) post vaccination serum (n = 5 per group) (B) binding to truncated GP forms depicted as response units. C Schematic of GP competition assay. Biotin labeled GP is immobilized on a streptavidin sensor. A streptavidin sensor is treated with biocytin and dipped in a solution containing serum preabsorbed by the competing GP. Serum antibodies which are not depleted by the competing GP bind to the GP immobilized on the sensor. Created in BioRender. Meyer, M. (2025) https://BioRender.com/w6beb8i. D Binding inhibition to immobilized GPΔTM, GPΔmuc or GPcl expressed as a percentage of total binding response unit values obtained without serum pre-adsorption. E Proportion of the antibody response binding to the MLD, GC and combined RBD, wing and GP2 regions. The mean responses of each group are shown as bars, with ± SEM. Significance between MARV and RAVV vaccine recipients measured by two-way ANOVA with (A, C) Sidak’s or (E) Holm-Sidak’s correction for multiple comparisons.